Hello. I am new to this forum and I signed up in hopes to get a little help with my 2006 GT.

The issue:

For a couple of months and almost $3000 later, my mustang has had an ongoing issue with a misfire. In every gear (especially 3-5th high rpms) my car starts to sputter and has very little power. I ran a diagnostics on it and came up with p0340 or p0390 code ( i do not remember exactly). I looked at many forums a couple of months back and saw that many people haad a similar problem and the answer was a new alternator. I went to ford service and got a new alternator. I installed it at home and still had a sputter.

The next step was to get my fuel pump tested. Everything was ok. Next I replaced the Fuel Filter since it is easy and cheap... still sputters. Next I upped my fuel pump to 25 PSI to see if it that would solve the issue... still sputters.

A couple of weeks ago I put brand new spark plugs and ignition coil boots on it and still.... SPUTTER!

Today I installed 8 brand new fuel injectors and still my car is sputtering. I am running out of ideas on what the issue could be.

Additional information about my car.

100,500miles
Steeda underdrive pulleys
Bassani SS off road x-pipe
Flowmaster Super 40's

(Installing my Steeda 90mm cold air and SCT BAMA tuner on monday when it arrives ups from AmericanMuscle)

I have replaced my alternator twice
spark plugs and the coils are 2 weeks old
Fuel Injectors are brand new as of today
all vacuums are tight

Any help is appreciated!

Thank you

 

I could be wrong but I would not install the CAI and tune until you get the misfire issue figured out.
Repost this in the tech section for detailed responses to your problem.

 

Well yeah... that's a given. I'm anticipating getting my gt fixed by then.

 

Well you didn't say that, so I was trying to give you a bit of advice. Good luck.

 

Didn't think I had to mention that I would not tune a car that's misfiring. I wouldn't sail a boat with holes on the bottom either lol. Thanks for the luck! Lol

 

Welcome. You might try asking your question in the Tech section for a better response.

 

Aviatormy,

If you're positive there's no vacuum leaks, then how positive are you that your exhaust is bolted up tight against the exhaust manifolds? That's the only other thing I can think of besides a typical vacuum leak, and an exhaust leak isn't likely to be cause a misfiring (although I've probably seen it a small handful of times).

I know this is barely helpful, but sometimes the unique or unusual symptoms are the hardest to fix.

Shane

 

Tried replacing the sensor? If the DTC that often shows up due to the alternator doesn't go away with replacing the alternator, it's a fair bet it's the sensor itself. Cost ya a whoppin $28 and 15mins time.

http://iihs.net/fsm/?dir=10&viewfile=Diagnostic%20Trouble%20Code%20(DT C)%20Charts%20and%20Descriptions.pdf
http://iihs.net/fsm/?dir=237&viewfile=Camshaft%20Position%20(CMP)%20Se nsor%20-%204.6L%20(3V).pdf

http://www.tousleyfordparts.com/part...ITION%20SENSOR