MyStang2010GB

Ok ... under hard acceleration the car stumbles around 4k rpm and then picks right back up again. The car has 33k original miles on it and was well taken care of. Is this possibley an issue with coil packs, wires or is this more of an issue with the IRMC plates??

shaunrc

I had the same problem with my gt and it was because the coil pack bracket broke and it came off the plug

MyStang2010GB

Checked and that is fine. more history, the car has sat for along time between periods of being run. 3000 miles in last 3 years. original owner had cancer and the car didn't get driven except by his wife every now and again. I had to replace tires (dry rotted) and shocks/struts/bushings on suspension due to dry rot. Any possibility the wires could be breaking down or packs themselves from same issue of car not being run...

skunk21

when is the last time you changed the fuel filter? yeah it is possible and a symptom of a high rpm break up is spark related but on the '96 OBDII cars you should have gotten a miss fire code, even the irmc will toss a code. another cause can be fuel related a dirty filter can be a quick easy place to go even more so with your limited use. If that doesn't work then get it on a good scanner to dig further since you may have a code pending or you may have to start testing each coil,etc.

Dbranham

Mine does it too.

Will be replacing coil packs, spark plugs, plug wires, fuel filter, and giving the engine a nice cleaning. Come Monday or tuesday whenever they come in. Already have the filter

I'll do the filter today maybe and tell you if that helps.

I'm at 146k so there is a slight difference lol

MyStang2010GB

The fuel filter was changed on 4/7/2012 along with oil/filter, tranny fluid and rear end fluid. The stumbling has gotten worse over the last few weeks which is why I was thinking it is spark related. The car has been driven more in the last month than it has in the last couple of years.

Clutch engagment is very high.... I adjusted it and it feels much better but still higher than I am used too. It was suggested that possibly the clutch going out could cause this but I would think it would be through the power band and not just in this 3500 to 4200 RPM range

I am the second owner.

shaunrc

What I would do and this is just me is clean your injectors your mass air sensor change spark plugs and cleans your throttle body then go from there I don't like using as scan tool cause it could give you a false reading for instance my buddy was throwing a code for the o2 sensors well when I checked it out his intake tube had so much dry rot that it split in half replaced the tube code went away

skunk21

good ideas. I agree I wouldn't use a code reader either for this but one that can read more and offer testing for sensors and circuits. A shop would have the more expensive scan tool for this I probally should have been more clear. You buddy also didn't get a false reading , once you get the code then you test the sensor and if it checks out then start back tracking the system it is on or the system that would trip the code. The code only is a start not the answer.

shaunrc

Maybe I should have worded it differently when I said false I meant he was getting ready to replace all his o2 sensors when they didn't need to be

skunk21

ahh gotcha. yeah some people will throw parts at the car or just replace what ever sensor the code comes up with, sometimes it works. I wouldn't replace all the coils though, they can be checked.

texastboneking

Two possibilities..
1. Clean the maf. That's what was wrong with mine and its an easy fix.
2. Check the imrc motor and make sure it is working.

skunk21

no code for the imrc? the ford contour would get a code 1519 for stuck closed or open I don't remember off hand which one, just curious. do the easy stuff like stated but if it doesn't work I'm still leaning on putting it on a reader.

texastboneking

Can throw a code. But if the linkage breaks or comes off and the motor still works there wont be a code.

skunk21

True .

Scothew

The IMRC actuator (motor) is my guess as well. They are supposed to open the secondary intakes at 3250, and if it doesn't or its getting erratic in its operation, your power band will be insanely slow and rough at the same time. If i remember right, you can acutally find the cables by hand back behind the intake where it goes to the plates and feel them move if the engine is revved up. maybe try that (although very carefully) to see if your getting any movement. There will be a cable going to each intake side.

texastboneking

Correct.
Reason I call out a dirty maf sensor is when the plates are closed the airflow is slower and the readings are not as picky through the maf. When the plates open the flow almost doubles and will not read correctly on a dirty maf. That's what mine was doing. Anything under 3500 rpm was smooth. When I tried to go above that it would stumble

MyStang2010GB

Bingo for what my symptoms are... I'll try and get to this on Saturday

Poisoned Pony

the IMRC's can stumble and store a code but not trip a light. I've had it happen on my old '96. I'm about to do a cleaning on my current '96 as I'm 90% positive that the plates are gunked up

Dbranham

I replaced my spark plugs and wires and mine no longer stumbles