[BabyBelugaGT]

I have 2001 Mustang GT that i bought a few months ago from craigslist. When I first bought it, the car ran great, I could hit redline no problem, but then the first time I took it to the track for drifting I started having problems. After a few runs, when i would clutch kick the car had absolutely no power and i couldn't break the tires loose. Then i took it off the track to test drive it and the car would not go past about 3k RPM. The drive home, i could hardly give it any gas or it would sputter almost like a misfire and especially up hills. But then after a few days it went back to normal. Then i took it back to the track a few months later and the same thing happened. This time the "misfire" wont go away. It really only happens when i give it hard acceleration like a hard shift or if im off the gas and then floor it immediately. I have changed the fuel pump, fuel pump module, Fuel rail pressure sensor, spark plugs, coil packs, throttle position sensor, crankshaft position sensor, and idle air control valve. Please if anyone has any advice, let me know! Thank you!

 

[my89foxbody]

You didn't list a fuel filter, I hope you replaced that but forgot to list it as items replaced. How many miles are on the car? Any mods been done to the car or is it stock?

 

[BabyBelugaGT]

Yes! I replaced the fuel filter first. It has about 150k miles. Only thing done engine wise is cold air intake. I was planning on doing fuel injectors next week and also I have an appointment at Ford to see if the PCM has a tune, and if so, get it reflashed to stock.

 

[wmburns]

Wow. Replaced all of those parts and no fix?

Do you have an ODB2 scanner? Even better one with graphing and data logging? Because if you did it might help to narrow down exactly what's wrong so that only the parts that matter are repaired.

Here's some information on an affordable Windows based unit.

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-forums/resources/forscan-odb2-scanner-w-elm327-usb.57/

If this were my car the first thing I would do is to graph RPM's, MAF flow, Fuel pressure, and timing advance. What we need to know is what is changing when this problem occurs. Look also at IAT, ECT, system voltage, EGR flow.

Also look at ODB2 mode 6 data under the "misfire" data. Which cylinders are misfiring?

 

[Jeremy Weigel]

Maybe partially clogged exhaust?