Bucking mustang

[timdsellers]

My car is bucking at low rpms at partial throttle and 1st and 2nd mainly. Idles and WOT perfect. Its an 01 gt. Maybe COPS? Any ideas?

[timdsellers]

Also, it has accufab 70 or 75mm throttlebody (not sure which) and plenum and bbk cold air intake. Pink top injectors(21 lbs). I also notice when giving it throttle at the engine when I gun it you can hear a kind of gulping sound and a bit of a studder but then sounds perfect.

[06V6Andrew]

does it have a cam in it?

[timdsellers]

Stock cams and PI heads.

[akagreg3]

Stock cams and PI heads.

are they factory? heads and cams untouched if not did you/have the cams degreed ?

[Blackout]

Sounds like its a air problem. There would be just a few things that can effect this. If your TPS is messed up, you have a vacuum leak, or you have a Mass-Air issue.

[timdsellers]

Supposidly the heads have been ported and polished but if I had a dollar for everytime I heard that I would be rich. Im not sure if the cams were degreed or not. But kind of doubt it. It was a brand new block and heads direct from ford. Now has around 2k miles on it. It looks like a donor engine provided the accesosories. I am also running a stock intake with adapters so it fits on the 5.4. The cams are stock though, that much I can tell for sure. I just got the car a couple of weeks ago and am working out the bugs from the engine swap.

[JIMS SVT]

May want to inspect the intake really well. Ive seen the factory intakes get a hole blown in the bottom and do something like your talking about. Cant really see it unless you look super close or remove it.

[akagreg3]

Supposidly the heads have been ported and polished but if I had a dollar for everytime I heard that I would be rich. Im not sure if the cams were degreed or not. But kind of doubt it. It was a brand new block and heads direct from ford. Now has around 2k miles on it. It looks like a donor engine provided the accesosories. I am also running a stock intake with adapters so it fits on the 5.4. The cams are stock though, that much I can tell for sure. I just got the car a couple of weeks ago and am working out the bugs from the engine swap.

my 4.6 was doing this when i put on my stage2 pi heads and pi cams, i changed every sensor i could find trying to figuer it out, cost me about 300.00$ in sensors long story short i paid someone 200.00$ to degree the cams had it tuned and it was awesome after that, alan at dirtydog will degree them for 250.00 but the motor has to be out of the car, and yes the pi intake are know to crack..... so check all the easy stuff first air leaks/hoes off sensor unpluged? best i can say is good luck

[timdsellers]

Thye other thing I am noticing is it doesnt do it all the time so would think if it was cams or something like that it would be a permanant thing. Its not that bad actuallty and can drive around it when it does happen. Just annoying. I am getting a tuner/data logger soon, so hopefully that will help.

[timdsellers]

NEW INFO. Trouble codes for crank sensor and misfires on 2,4,7,8 cylinders. Still seems to run ok though.

[akagreg3]

NEW INFO. Trouble codes for crank sensor and misfires on 2,4,7,8 cylinders. Still seems to run ok though.

change the crank sensor its cheap, and see if its getting fire from those plug wires, if none of that works take the timing cover off and change the crank trigger wheel or at least check it.

[timdsellers]

Yep, that will happen soon. Thanks!

[RACEME]

It can also be a bad or dirt maf meeter. Just unplug it and go for a ride in limp mode. If it acts fine, then you need to work on your meeter. I had this happen after a couple nitrous backfires.

[timdsellers]

I deleted the codes just to make sure it was an actual current fault and now no check engine light. WTF.

[akagreg3]

I deleted the codes just to make sure it was an actual current fault and now no check engine light. WTF.

hmm? after you ran the car for like 5-15 mins did the light come back on or is it just not giving you any codes at all? if so you may have a ECU problem.

[timdsellers]

I havnt driven the car. Just turned it on and let it run for a few minutes and noticed it didnt come back. Will do more investigation asap.

[Blackout]

Starting and letting a car sit isnt going to do much of anything unless there is a big problem with a sensor or sensors. You must drive the car in order for the computer to go through a drive cycle. This will take any where between 1/4 mile to 3-4 miles.

Drive the car around and see what it does.

[timdsellers]

Yep, drove it around for a good 10 miles. No check engine light.