Missing and rough idle

[Festus]

This week I noticed that my car is "missing" and the idle is rough. It's idling between 400 and 500 RPMs and periodically the idle will just drop almost to a stall. On the road it is noticably "missing". As I said it just started this week and I haven't done anything to it. I'm running 93 octane gas in it. It's almost as if I were running 83 octane gas instead.

Anybody have any ideas?

Eric

[MMdriver03]

The same here @22,000 miles :help:

[Murader03]

How about bad gas! Could have picked up water from your fill up just before the problem started. Could also be a bad plug, coil pack, etc. Any light indications on the dash? Could be numerous things. Might be time for a service appointment!

[MMdriver03]

I have only been using Mobile 93 octane.I spoke to dealership and was told others have also commented on this problem.

[cyclone03]

You can have the dealer reflash the ECM with the latest cal.codes.(search the forums here,there is a TSB on the problem)That will "help" the problem some.
I had it done to mine but for some reason I felt the "fix"degraded over time.
At long last I'm going to be a band wagon jumper and say have Dennis reflash your computer,I had mine done in Ennis,huge difference in drive ability.

[nhinterceptor]

Mine had the cold stumble/rough idle.

SSM 16428 fixed it, do a search of 16428 and you will find a bunch of threads.

- Dan

[MMdriver03]

Thanks Dan , I will do a search and bring that info to dealership.

[Marauderman]

Well, for whats it worth-

If I start mine--let her warm up where she is above the cold mark then I know all of her oils are up in the engine and warm--I do not have a problem--

BUt if I don't--I get your problem --until she decides she is thourougly oiled and warm and then it's a bit like a cough --or clearning the throat--

So I always let her warm up --no problems now--after all- she is a high performance engine--so why no let her get a chance to get herself ready before asking her to perform.. it works without problems that way for me......like I said--my .02 cents worth---..Tom

[Festus]

It's missing even on a nice hot engine. I just filled up the tank today from a different gas station just in case I got a bad batch from the one I normally go to.

Eric

[67435animal]

Originally posted by marauderman
Well, for whats it worth-

If I start mine--let her warm up where she is above the cold mark then I know all of her oils are up in the engine and warm--I do not have a problem--

BUt if I don't--I get your problem --until she decides she is thourougly oiled and warm and then it's a bit like a cough --or clearning the throat--

So I always let her warm up --no problems now--after all- she is a high performance engine--so why no let her get a chance to get herself ready before asking her to perform.. it works without problems that way for me......like I said--my .02 cents worth---..Tom

Tom, mine will stumble only is I start it cold in the morning and run it immmediately. It smooths in about 1/2 mile. If I warm it up, no problems. I have had cars with chokes that behaved much worse than this 'cold stumble'. No big deal in my opinion.

Bob

[Mark McQuaide]

No stumble here but a bit of a lumpy idle. Had the dealer put the latest PCM program in, no difference in the idle. No other problems, though, so I guess the idle is normal.

[MMdriver03]

My rough idle and stumble became a check engine light.(22,000miles) Took it to my favorite merc dealer. Got the call this afternoon! I was told that #8 cylinder is not getting enough comppression! :depress:

[nexstar7]

you must follow up on them. because they will stiff you. get all the info as to why and post it . i have the same problem and so do alot of others.

[nhinterceptor]

Re:MMdriver03

Low compression on #8 - Didn't want to hear that!

I am loosing intrest in this car really fast, starting to regret getting rid of the old cars.

Ford had a problem with the early 5.4 in F-150's and they denied it and kept wearing customers down with BS. There was a long discussion in the F150 Online forum, it was a piston slap problem.

My MM has under 7,000 miles not looking forward to more issues.

-Dan

[nexstar7]

goodluck for you brother. i have 5000 on mine. it will be 1yr old. god help us all if this turns out to be a f--k by ford

[jgc61sr2002]

[QUOTE]Originally posted by MMdriver03
My rough idle and stumble became a check engine light.(22,000miles) Took it to my favorite merc dealer. Got the call this afternoon! I was told that #8 cylinder is not getting enough comppression! :depress: [/Q UOTE] MM - Hope it works out for you, in a timely fashion. Please keep us posted.:(

[MMdriver03]

The dealer said it would be in for about one week. They are going to pull the head(or heads)to find the problem.

[Fin Harder 92]

Guys, This is my first FMC product and I gotta say I'm not real comfortable with the problems being written about on this board. I've been a member on other car forums and I know how a few isolated issues can become "epidemic" and the "problem" is magnified. I don't think that's what happening here.

I heard a very respected man in the MM community say that he wished Ford would have put this package together and brought back a name from the past. That would have sparked more interest (advertising) and more dealers in the network to directly service these cars. These are all valid points and would have made it a stronger product for sure. It wouldn't however fix the QC issues that are being talked about here.

Before I bought my MM I swore I'd never buy another new "American made" car (No such animal really). The package put together by FMC changed my mind and an extended warranty calmed my nerves. That is untill I began to read about problems incurred by those dealing with LM dealers over warranty work and my own experience with less then knowledgeable employees. By contrast, I am met with a welcome and my questions answered when I take my wifes well built and smooth running Volkswagon Jetta TDI in for scheduled maintenance.

I wish you the best possible outcome and hope that the manufacturer/dealer do the right thing in a timely manner.

Take Care

[MMdriver03]

I suppose they could of told me i had a bad plug, reset the engine light and sent me on my way.......They did the compression test and now will pull head and give me a loaner(01GM) and fix problem. I still love this car and feel confident that this dealership will come through for me.

[67435animal]

Originally posted by MMdriver03
I suppose they could of told me i had a bad plug, reset the engine light and sent me on my way.......They did the compression test and now will pull head and give me a loaner(01GM) and fix problem. I still love this car and feel confident that this dealership will come through for me.

It sounds like the dealer is doing everything possible to resolve the problem. Hopefully, it will be something simple to repair like a stuck valve.

As I read the forum posts, I read about a lot of us having a lot of fun and deriving a lot of pleasure from our MMs. Also, I read a lot of posts about problems. I suspect that we all have very high expectations of the car because it performs so well. Many of us have modified it to push it even harder than Ford intended.

Having owned many older muscle cars over the years, and having been responsible for every repair (whether I did it myself or paid someone more capable), I can tell you that the sweetest words I have heard recently were, 'Yes, that should be fixed...under your warranty."

The MM is a great car. I am very pleased that Ford has built it. GM does not even compete in this area. The MM is unique in that it is a performance sedan with rear wheel drive (I cannot stand FWD cars!) We expect a lot and we should. Be careful not to let posts of various problems cause you unnecessary concern...unless problems really happen to you, they are not problems at all, just things to be aware of.

Enjoy your MMs; as I said, the MM is a great car!

Bob


Others:

1967 Corvette Coupe (L71, M21, 4:11 POSI)
1967 Olds 442 (350HP, 440 lb ft torque, TH400, 3:23 POSI)
1966 Mustang GT (289 A-code, auto, AC, etc - wife's Pony)
1997 Taurus wagon (wife's grocery getter - and FWD) :help:

[MMdriver03]

Animal I agree , some posts may be real downers. I just read TA on another thread having similar problem to mine having to remove heads and all ...Maybe i can convince them into replacing my heads with some of those polished and ported ones . :beer: :beer: :beer:

[67435animal]

MMdriver03, I recently purchased the ESP Premium package. After asking a number of friends and my mechanic (for the older cars), I was convinced that the price represented a good value. I can rest easy knowing that I am covered (less deductible) if anything goes wrong for 75,000 miles.

Bob

[MMdriver03]

I agree with you animal, I also have ESP package. They repair up to contracts end and then the real fun begins! THATS when i drop a stroked ,blown motor in this bad boy!! Until then i will remain stock

[Dennis Reinhart]

Originally posted by Festus
This week I noticed that my car is "missing" and the idle is rough. It's idling between 400 and 500 RPMs and periodically the idle will just drop almost to a stall. On the road it is noticably "missing". As I said it just started this week and I haven't done anything to it. I'm running 93 octane gas in it. It's almost as if I were running 83 octane gas instead.

Anybody have any ideas?

Eric

Does the car have a chip

[MMdriver03]

same problems Dennis (and worst) and no mods

[Dennis Reinhart]

Well if its a engine miss I would have the dealer check the engine with a WDS this can quicly pinpoint a week cylinder, hopefully its simple not Major again the early model 4.6 DOHC motors were prone to head problems, let us know what they determine

[Festus]

Originally posted by Dennis Reinhart
Does the car have a chip

It was an ID-10-T problem. I ran some octane booster in the car and fouled the plugs. Got new plugs and she runs fine again.

Eric

[67435animal]

We go through the octane booster discussion on the Corvette Forum every month. Octane boosters are a waste of money. When they say raises octane 8 points, that means more like .8.

They leave rusty colored deposits all over your upper cylinders reaking havoc on the valve train, pistons and definitely spark plugs.

Bob

[RF Overlord]

This is from an article in Popular Hot Rodding magazine:

Octane boosters offer little help in the quest for higher octane. Most popular street-legal octane boosters claim increases in octane ratings up to five points, and those boosters intended for off-road use only claim up to seven points...Nine of the most popular retail octane boosters were put through a series of tests to determine where the consumer could get the most bang for the buck. The test results were verified by an independent testing facility, using several brands of regular unleaded and premium gasolines, just to make sure everything was legit.

According to Mark Borosky, Vehicle Test Engineer for Sunoco, "Of the nine octane boosters tested, none showed a significant increase, and one actually lowered the octane number of the test gasolines." Testing repeatedly showed a maximum increase in octane of 3.5 points by only two of the six street-legal octane boosters when the recommended treatment rate was blended with lower base 87-octane gasoline. The best the remaining four products could muster was less than a one point increase. "While clearly no one would actually use an octane booster in a low base octane fuel, we wanted to give the manufacturers the benefit of the doubt relative to their claims of five-to-seven point increases" explained Borosky.

When tests were performed using 98 and 94-octane fuel, even the two best products from the previous tests produced a disappointing 1.5 to 2 point maximum increase. The remaining four street-legal octane boosters showed less than a .5 point increase. Those products designated for off-road use only didn’t fare any better than the street-legal products. Subsequent tests where the dosage of octane booster was doubled, tripled, and even quadrupled produced only minimal improvements in octane, regardless of the base octane hum-ber of the test gas. In fact, quadrupling the treatment rate of the most powerful additive produced only a 3.5 point increase in octane when added to 98 premium, resulting in a cost of $3.25 a gallon.

I found that using 104+ Octane Boost in my '68 Buick GS did very little or nothing...even when I tried 2 bottles, I STILL couldn't set the timing anywhere near where it belonged without pinging...and like animal said, it leaves all manner of ugly deposits on the plugs...

[67435animal]

My 67 442 is set to run on 93 and it does so quite happily. The 435 car likes octane so I have to mix 110 octane racing fuel (sold within 3 miles of my house!!) with 93 SU to get an effective octance rating of around 100.

The car loves it and you can say it is expensive but, it rarely gets out and I use a tank every month or so.

Save your money; ignore the hype. If you need octane, buy racing fuel.

Bob

[Dave Compson]

I know its early, maybe i am still asleep. But was the verdict on the #8 cylinder with low compression was from bad plugs? Bad plugs from using octane booster?

[Dennis Reinhart]

A fouled plug should not lower compresion

[MMdriver03]

I know its early, maybe i am still asleep. But was the verdict on the #8 cylinder with low compression was from bad plugs? Bad plugs from using octane booster?

No that was not the verdict. I am still waiting to hear from dealer. Check engine light came on and I could hear what sounded like a popping sound from tail pipes at idle.I also had stumble and rough idle,surging also ...I apologize if I confused things here by not starting a new thread on this subject.I will post results as soon as I get them (on this thread). O ya my 300 A is totally stock.:)
__________________

[MMdriver03]

Almost forgot, the dealer did say that it had loss of compression in cylinder #8. They are pulling head or heads and should get back to me in couple days.

[TripleTransAm]

Wow. Maybe your valve guides got so bad that the valve won't seat properly (but, damn! those valve springs should have at least forced the valve to settle into its seat somewhat properly, even if it protested and made noise doing so!). Just a wild a$$ guess at this point, I'm definitely interested in knowing what they find.

[Dennis Reinhart]

The early 4.6 DOHC had problems with the heads it been disscussed many times if this is the case they will replace both heads under warranty

[MMdriver03]

The early 4.6 DOHC had problems with the heads it been disscussed many times if this is the case they will replace both heads under warranty

The build date was 6/02 .... I hope to hear from dealer tomorrow. Thanks Dennis

[MMdriver03]

Heard back from dealer today regarding low compression in #8 cylinder. I was told it was do to a defective head and they will be installing a new one.

[Dennis Reinhart]

A pair I hope

[MMdriver03]

Dennis, I told the service manager that I was concerned about both heads. He said that only the one that failed shall be replaced(per ford motor co.) I do have a 100,000 mile warranty if that matters?

[Dennis Reinhart]

well that is plain stupid, I am not bashing you this is the most assnine thing I have ever heard of, its a known fact that the early production heads are bad I woull not settle for any thing less that both heads or a new motor.

[MMdriver03]

[quote/]well that is plain stupid, I am not bashing you this is the most assnine thing I have ever heard of, its a known fact that the early production heads are bad I woull not settle for any thing less that both heads or a new motor.


__________________
Dennis
Dennis , I thank you for your reply and I don't feel as if you are bashing me personally. I know that these issues are really starting to aggravate a lot of us.... especially those of us with these types of engine failure. I did not personally know of any one getting new heads or engines due to valve guide issues ,correct me if I'm wrong (I probably am)... What I did do was post my problem, got as much advice as I could and did some searching. I thought to get them to supply a new head was a far greater accomplishment than settling for new guides...Dennis if you or anyone else has any type of print material avilable i would love to go to dealer with it first thing in the morning. All I could find to get the new head out of them was this attached claim...(And I agree,TWO heads are better than one) :)
If your 2003 Cobra Mustang exhibits this condition, Ford may replace the cylinder head and cam assembly. The replacement cylinder head part number is: 3R2Z-6049-GA. Owners are advised to have their vehicles inspected before the warranty period expires

[Dennis Reinhart]

Ford has known for over a year there was problems with the first production run on the heads, This covers the 03 Cobra the 03 Mach 1 and the Marauder, they have not recalled them, for the obvious reason, and they can look for a reason to invalidate any high warranty claim, for example they will look and see if a chip has been installed, I would stand my ground, both heads need replaced or the entire engine I would contact the Ford District Rep, and calmly professionally explain your opinion.

[carfixer]

As a dealer tech, I can tell you that the dealership does not make the call on this. Ford calls back warranty parts and inspects them to determine if they were in fact faulty. If they determine that a non-faulty part was replaced, the dealer is subject to charge-back for the whole repair for over-repairing the car. They would certainly consider 2 heads over-repairing the car. The management usually will not take that chance. Unless there is a Ford published service message or TSB, the dealer has no choice but to replace the defective cylinder head only.

As far as replacing the engine, Ford requires the dealer to phone into a hotline for engine exchange approval. They use a cost of repair versus replacement formula. They make the tech perform many inspections and tests. The may even require digital photos. They also have sent out inspectors to verify the test and inspection results. If cost of repair exceeds replacement, that is the only time they will authorize a replacement.

Like Dennis said, request a meeting with the local district rep and come armed with as much information as possible.