Need u engine guru's help please...

[gi_jackii]

if any of yall can help it would be great... ive got a stutter when im cruzing at a constant speed and cant for the life of me figure out what it is. it doesnt do it at WOT, just at a consistant rpm. it feels almost like a miss, but a REALLY long one. ive changed the fuel filter, cleaned the MAF, and am going to go ahead and run sea foam through it tomorrow/ change the plugs and oil. anyone have any suggestions on what it could b? (04 mustang GT, manual trans) thanks in advance

also, it didnt do it before we recently changed the clutch...:shrug:

 

[slider701]

Is it always at the same RPM....like in 3rd and 4th??? Could be a balance issue with the pressure plate. Could also be the dampening springs in the clutch plate.....they help with gear chatter and rollover dampening...highly unlikely but always a possibility

My #1 choice would be a small vacuum leak.....somewhere at the back of intake area. Pull all your vac hoses off and reseat them.

 

[JMD0346]

Sounds like spark breaking down possibly.

 

[wvmystichrome]

Does the GT motor have plug wires? If so change them. My wife's 95 T-bird with the 4.6 kept doing that. So I changed plugs. Nope still there. I went to a buddy who works at Ford and he put the laptop in the car in my lap and we went for a drive. Plug wire #6 was dead. I went out and bought (big mistake) a cheap set. They lasted 3 months (Advanced Auto brand.) Finally got a good set at another dealer thats been on the car for over a year now and it is just starting to act up again. OBTW Advance sold me a set of life time plugs and I had the receipt but they said what they gave me was not life time warrantied they were the cheap ones. They would exchange out.

 

[gi_jackii]

no, its not at any particular rpm. and its done it in every gear so far. far less likely in 1-3rd though. thanks for the input so far guys

 

[meaty mac]

Does the GT motor have plug wires? If so change them. My wife's 95 T-bird with the 4.6 kept doing that. So I changed plugs. Nope still there. I went to a buddy who works at Ford and he put the laptop in the car in my lap and we went for a drive. Plug wire #6 was dead. I went out and bought (big mistake) a cheap set. They lasted 3 months (Advanced Auto brand.) Finally got a good set at another dealer thats been on the car for over a year now and it is just starting to act up again. OBTW Advance sold me a set of life time plugs and I had the receipt but they said what they gave me was not life time warrantied they were the cheap ones. They would exchange out.

All new edge V8's have COP's

 

[meaty mac]

no, its not at any particular rpm. and its done it in every gear so far. far less likely in 1-3rd though. thanks for the input so far guys

This is a real head scratcher. since you say that it doesn't really do it in the first three gears, it sounds like it really does it when there's a load on the engine. (4th and 5th)
Do you know of a good mechanic or tuner in your area? datalogging may reveal what's going on when you replicate the problem. ( if it is fuel or spark)
Since you said it happened when you changed the clutch, you would have to figure that would be the source of the problem though. maybe take it back to whoever did the install. he may have to go through it again. good luck.

 

[gi_jackii]

got it, thanks to all... it was the fuel pump not sending a constant pressure... dont know y it wasnt throwing a code but at least i know what it was now. that was buggin the piss out of me. thanks again for the n-put guys