Car still idles rough! Now what??

[Riceater52910]

Heres the problem, i bought my 04 cobra from the dealer about a month ago. The car was already pullied, along with having a JLT cold air with a Borla cat back. Though bad thing is i dont know what kind of tune was done to the car, it did not come with a programmer. Since ive owned the car it has never idled smoothly, uless the AC is on. When i rev it up black smoke dumps from the exhaust, nothing crazy just a little initially. I tried replacing the Fuel rail pressure sensor, did nothing. So then i bought a Diablo tuner, which i received in the mail today. Install the 91 octane pulley tune, and the car still runs the same. Is it really bad that i installed over an unknown tune? If not, then what could be causing the car to run like this? Something not related to the computer?

 

[Miamifan1354]

If it had a pulley, then I would take it to a shop, have it dynoed and have the A/F checked. Dealership may have flashed it with a stock tune and you could really be messing up the engine. Stay out of boost and get that thing checked out.

 

[nealc]

get it to a dyno or install a wideband. Do not beat that car. It is scary not knowing how well a car has been tuned.

 

[BoostFiend]

I wish people wouldn't buy pullied Cobras from dealers unless they have all the tune info. I have heard tooooo damn many horror stories. Good luck man. Get it to a shop and get it tuned.

 

[Riceater52910]

The traction control was tuned out when i bought it so i know there was some kind of tune... My guess would be some kind of custom tune. I assume if there ever was a predator tune on it the owner deleted so he could sell his tuner on the side, being that it did not come with the car. I mean it runs good going down the road, cant get traction till third gear. Something is not right though, know of any good tuners in the SW Missouri area??