[BLK03stang]

I have been trying to figure this out so now im turning too you guys for help i have a 03 mustang gt with two valve motor.... and a about 1500 rpms my car seems too studder but as soon as it hits 2000 rpm it stops... and also this is the really wierd part... if i put a full tank of gas in it 91.... it cuts out and stops running and just runs like crap... but 30 min on that tank of gas it runs fine after that... i have changed plugs put ngk iridums in.... also omed injectors and coil packs.. everything checks out okay...also put new fuel filter in.. can anyone help me.. the car doesn't have much for mods.. just a diablo programer and cool air intake..

 

[ReverendDexter]

Stick or auto?

 

[BLK03stang]

stick.. sorry left that out..

 

[carnut59]

any gear?

 

[BLK03stang]

it doesn't it in every gear so if i got from first too third it's horrible

 

[BLK03stang]

it just really weird i've checked vac lines.. and all that stuff...

 

[ReverendDexter]

Does it do it under light acceleration, too?

 

[BLK03stang]

yea it does... just anything under 1500 just horrible studder. the whole full tank thing is the same way...

 

[ReverendDexter]

Well, under 1500 doesn't surprise me... my 4v doesn't drive for crap under 2k.

OHC motors need more rpm than that, I've never seen one that was happy under about 1800 rpm. Meanwhile my pushrod motors will pull from just over idle.

With the gas thing - if you run 91 consistently, does it do the stuttering thing every tank? Or just when you swap from low octane to high?

 

[BLK03stang]

i run 91 all the time...every time for the past month excpet once.. and that time something triped my check engine light.. and it was blinking but then shut off before i could even think about pulling over and putting the computer on it too check it...

 

[BLK03stang]

and for the studder thing it didn't do that when i bought the car..so thats why i wondered y it's doing it...or what it is for that matter...