Throttle response - Hesitation/delay off-idle

[Mote]

I installed a K&N CAI, then a Reinhart tune (otherwise stock) - I now notice a slight delay when revving the engine. Maybe just .1-2 tenths of a second, but it's there. I can hear a rush of air, then the engine revs.

This is from idle. I read through the thread below. There was no resolution. The IAC valve seems really unlikely - It addresses other symptoms. Should I be persuing the "Load_With_Failed_MAF table" with DR? Any other thoughts? Thanks so much


http://mercurymarauder.net/forums/showthread.php?t=59163&highlight=hesitation

[LeoVampire]

Maybe the air filter in the K&N kit had too much oil on it and saturated the MAF.

Get some MAF specific cleaner and see if it solves the problem.
See if you can find an air flow leak along the new CAI you installed.

Plus the car does have to learn how to work with the new stuff you put on have you driven it around to see if it gets any better as you drive?

Did it start after you did the tune change or after the CAI?

[musclemerc]

Check all the connections on the CAI, it sounds like unmetered air getting into the system.

[Mr. Man]

You disconnected the battery when you put the K&N on right? Like above the computer may need to relearn your cars wants and needs.

[SpartaPerformance]

Sounds like the tune may need to be adjusted.

[Mote]

My memory is unclear at which point this started. Since it is very easy, I will load the stock tune and check that.

I checked the CAI connections and they seem good - I just reinstalled the air tube with new clamps and rubber sleeve thingies. I don't hear anything(whistling etc). I had asked K&N for preferred methods to detect air leaks and they had no suggestions.

I have MAF cleaner, as I cleaned it last fall, so I can try that next.

Does the "Load_With_Failed_MAF table" have credence?

[Mote]

I rechecked all the CAI fittings - They all seemed good.
* What's a recommended method for checking for air leaks??

Then I loaded the stock tune and drove around for a while. The hesitation was worse(1) :-( Then I loaded the DR tune back, disconnected the battery, took the MAF out and inspected - It looked fine. I cleaned it anyways with MAF cleaner. Reconnected the battery after 30m. Started it up and drove around for a while.

The slight hesitation is still there! Otherwise the car runs great. Any other ideas? Thanks folks.

(1) This tells me it didn't used to have this hesitation. Hrm - btw - I couldn't believe what a dog it was with the stock tune.

[MMBLUE]

How bout oil in the upper intake? Try a throttle body cleaning.

[LeoVampire]

You could have an unrelated problem that just happend to pop up @ the same time as doing the CAI and tune install.

That does happen it sucks because it takes time to figure out what started to screw up on you.

You could have a weak coil problem that sudenly started to rear it's ugly head or a number of other things.

[Mr. Man]

You could have an unrelated problem that just happend to pop up @ the same time as doing the CAI and tune install.

That does happen it sucks because it takes time to figure out what started to screw up on you.

You could have a weak coil problem that sudenly started to rear it's ugly head or a number of other things.
Wouldn't the computer throw a code for a bad coil?

[RacerX]

And you haven't done anything else recently? No spark plug gapping, changing, different gas type...

[magindat]

Wouldn't the computer throw a code for a bad coil?

Not always. Especially if it's water in the plug pits. It will just misfire.

[magindat]

Take all of it off and clean the hell out of your throttle body. If you want REAL throttle response, buy an ACCUFAB.

[Mote]

And you haven't done anything else recently? No spark plug gapping, changing, different gas type...

Nothing. I did clean the engine off 3 months ago. Windex and very light mellow rinse. Would a coil misfire be undetectable, with the only symptom be an off-idle-only slight hesitation?

[BLACKMARAUDER04]

Did you change your plugs to copper with 1 colder range lower?
The tune will eat right through platinum plugs. I got mine really cheap from rockauto.com. Here is the link to my thread.

http://www.mercurymarauder.net/forums/showthread.php?t=40351&highlight=SPARK+PLUG

[Mote]

Did you change your plugs to copper with 1 colder range lower?
The tune will eat right through platinum plugs.

In 2 weeks? No, I haven't considered new/different plugs at this point. Will work plugs cause a hesitation off-idle?

[4play]

ohhhh yaa.. pull them out and have a look.

[LeoVampire]

Nothing. I did clean the engine off 3 months ago. Windex and very light mellow rinse. Would a coil misfire be undetectable, with the only symptom be an off-idle-only slight hesitation?

No if a coil is not really failing it will not set a code. Chances are unless water is getting into the coil covers from rain ya it could jump the spark if the rubber boots are week and there is no dielectric grease between the spring and spark plug to ensure a good connection between the 2.

Again all any of us can do right now for you is guess on what might cause the problem. There might be shops around that will do a diagnostics for you on the spark system and load test for a low amount of money to @ least eliminate that as a problem.

Right now I would say there is also a chance the throttle possition sensor could be acting up as well on you. There is an ohms test you can do to check it out.

http://fordfuelinjection.com/index.php?p=30

And you can use this thread to do a test of the coils if you want to do it all yourself instead of hitting up a shop.

http://www.v8sho.com/SHO/CoilOnPlugTest.htm

[Mote]

I installed new plugs (details in another post) - Autolite XP103's. The hesitation isn't completely gone but it is diminished. I want to hook up with another marauder so I can see what throttle response is on another car.