stumbling at low engine speeds

[mrjones]

My 04 with 152K on it seems to have developed a weird problem. I've heard some others mention something similar, but I haven't seen it described the exact same way.

When the car is 2nd or above with the TC locked up at very low engine speeds, if you accelerate moderately, not enough to unlock the TC or downshift, the car will buck or stumble as if the ignition is being cut off momentarily. It's very brief, and only at those low engine speeds.

I've experienced TC shudder in some of my other Fords, and this ain't it. It just feels like power is cut to the entire ignition for just a tiny fraction of a second. At higher engine speeds, approaching 1800rpms or more, it doesn't do it.

I have no check engine light or stored codes.

I thought it might be a bad COP, but it's not a miss on only one or two cylinders, it's as if the entire ignition has been cut.

Any ideas?

[CBT]

What all have you cleaned or replaced in those 125,000 miles?

[mrjones]

What all have you cleaned or replaced in those 125,000 miles?

It's actually 152K, and I've done basically nothing. I bought it last year from a little old lady here in town. I'll have to go back through the records that I got from them when I bought it, but it has complete maintenance records. The older couple that owned it before took it back to the L/M dealer for all maintenance. I remember seeing invoices for regular services including plugs, etc.

I would say that it's had better treatment than the one that I bought new!

[RacerX]

Try the simple, cheap fixes first. Get some MAF cleaner and clean the sensor. Check your air filter. Maybe run some Techron through the tank. Trans fluid smell/look good? Check plugs yourself. Who knows if they really did all that work or f something has changed since.

[JimmyXR7]

Try the simple, cheap fixes first. Get some MAF cleaner and clean the sensor. Check your air filter. Maybe run some Techron through the tank. Trans fluid smell/look good? Check plugs yourself. Who knows if they really did all that work or f something has changed since.
My Marauder just started to do the same thing this last week.
I have been purchasing the cheap gas on a regular basis for the last 6 years. The last weeks tank full was Rotten Robbie rather than USA gas. Yesterday I checked my records and the last time I purchased Chevron with Techron was about 1.5 years ago. I was purchasing Chevron around every 4th tank, so I decided Chevron for my next tank.
It is a good suggestion to run a tank of good quality gas (with the extra cleaners) through your Marauder engine.
Jim

[Vortech347]

Holding really light throttle in mine between 1500-1800rpm in 3rd tends to shudder a bit.

I'm thinking I'm due for a plug change. If that doesn't fix it I may pick up a set of coil packs. Anyone have an idea to narrow it down to just 1 that might be bad?

[71cyclone]

Holding really light throttle in mine between 1500-1800rpm in 3rd tends to shudder a bit.

I'm thinking I'm due for a plug change. If that doesn't fix it I may pick up a set of coil packs. Anyone have an idea to narrow it down to just 1 that might be bad?
I had the same problem this week. I took the Merc to Superior racing tranmissions in M.D. ,they road tested the car . 10 minute test drive . the outcome was to replace the coils. the Snap on scaner showed no codes .the digital ohm meter showed very low resistance with 4 coils . Superior trans's diagnostics were correct, R/R coils punch ticket and drive on:beer:

[71cyclone]

Oh almost forgot %%% / Trans was flushed and ford friction multiplier additive was added [ 5 dollar ] plugs were changed at 65.000 .shudder problem was recent at 71.000

[MERCMAN]

My car has had the same issue for 2yrs. Datalogged it, nothing showed up, all parameters were in normal limits. Leakdown test, stess test on coil packs, cleaned MAF, changed plugs, no problems found Took it back to Ford(under warranty)and just left it.

The answer...

EGR valve, once the EGR valve was disconnected, the stumble was gone. Replaced the EGR valve and she runs like a pickleseeder.



NOTE!

The original EGR valve had a metal gasket with a hole .6 inch ID, the replacement had a gasket with a restricted hole about half the size. My wrench believes that the wrong gasket was installed at the factory. Why it took 42K miles for it to act up is a mystery. Hope this helps.

[Odinson]

COPs should be replaced at that age. Sounds like my hesitation and that was at 63k! Higher rpms will power through it and mask the problem. Between 1500 and 2500 at speed (30mph) an observant driver can pick it up.

[lifespeed]

COPs are a very likely candidate. These are hard to diagnose analytically when they are intermittent. Change the whole set, don't try to find the bad one. They appear to be poorly designed from the factory. New COPs have a different part number.

Should be only $400 for all 8 if you get a good price ;)

[Marauderjack]

COPs should be replaced at that age. Sounds like my hesitation and that was at 63k! Higher rpms will power through it and mask the problem. Between 1500 and 2500 at speed (30mph) an observant driver can pick it up.

I have over 237K miles on my original coils but have Granatelli connectors and they still work very well!!:beer:

I have said it before and will repeat it here.....high resistance in the "springy thingies" from Ford will kill coils over time!!:argue:

Try solid connectors before you buy a complete set of coils.....my $0.02 FWIW!!:D

[lifespeed]

I have over 237K miles on my original coils but have Granatelli connectors and they still work very well!!:beer:

I have said it before and will repeat it here.....high resistance in the "springy thingies" from Ford will kill coils over time!!:argue:

Try solid connectors before you buy a complete set of coils.....my $0.02 FWIW!!:D

I am glad you haven't had to buy a new set of coils. But, if you hadn't noticed, many of us have had to replace them. Based on the number of failures, these coils are junk. I don't think Ford issued a new part to replace them because of their shining success.

Mine also started sputtering at around 60K miles. And I did try the Granatelli connectors first without curing the problem. As far as high resistance, those "springy things" are wire. How much resistance do you think a wire has compared to the air gap of the spark plug? Near zero. Coils are designed to ionize the high-resistance gap of a spark plug, and should have no problem driving both a high and low resistance load. Besides, spark plugs have resistors built into them. So your theory is unlikely to be correct. Besides, the new ford coils have the same connectors, although I can't yet say how long the new design lasts.

[Marauderjack]

I am glad you haven't had to buy a new set of coils. But, if you hadn't noticed, many of us have had to replace them. Based on the number of failures, these coils are junk. I don't think Ford issued a new part to replace them because of their shining success.

Mine also started sputtering at around 60K miles. And I did try the Granatelli connectors first without curing the problem. As far as high resistance, those "springy things" are wire. How much resistance do you think a wire has compared to the air gap of the spark plug? Near zero. Coils are designed to ionize the high-resistance gap of a spark plug, and should have no problem driving both a high and low resistance load. Besides, spark plugs have resistors built into them. So your theory is unlikely to be correct. Besides, the new ford coils have the same connectors, although I can't yet say how long the new design lasts.

Suit your self "Mr. Wizard" but the springs are mild steel and get rusty over time.....GC's are SS!!:rolleyes: My car has not missed a beat since I got the Granatellis 6 years ago!!:beer:

BTW, I am just trying to help out here and don't appreciate your terse crappy reply!!:shake:

[screamn]

If you find the problem and it's your coil(s) check out Sparta Performance. They have coils for MM and at a reasonable price.

https://ssl111.webhosting.optonline.ne t/spartaperformance.com/merchantmanager/product_info.php?cPath=53&products_id=356

[mrjones]

All good info.