running shitty...too much air maybe?

[nasty99]

still idles funky, bobs up and down as i coast to a stop. and it does feel like it pulls like it used to. i have a 65mm tb, and a jlt cai. some people say i dont need the big tb and that the jlt is pretty big for not having it tuned. and right now i dont wanna spend the money on getting it tuned. i cant get it to run right somethin is always going wrong. anyone know what the problem is with my idling and why she isnt running good? my check engine light is on as well throwing off the IAC and some o2 sensors naturally with my o/f xpipe. however i just got my iac replaced last year.. any ideas??? please help. im about to just put the stock tb and intake back on.

 

[nasty99]

like it doesnt pull like it used to**

 

[SilverNotch]

I was having idle drop problems with my 2001 Cobra. It has a jlt cold air as well. I bought a predator tuner and the performance 93 octane tune fixed it. I also, cleaned the throttle body,iac, and maf. Make sure all your piping is hooked up properly and there are no air leaks. If you need more advice let me know.

 

[GreySVTSnake01]

How long have you been running the off-road x-pipe? I could be wrong about this but I think if you don't turn off the rear O2's with a catless pipe it's going to throw your A/F ratio off. If you're having idle issues and your computer is throwing IAC error codes I think probably you might want to check your IAC. Other than that a bigger throttle body isn't really going to affect performance one way or the other from what I have seen. Maybe gain 1 hp and lose 1 ft of tq. Last thing I would check is exhaust leaks between your cross over pipe and manifolds. Aftermarket pipes just don't fit as snug as factory pipes. I had a small exhaust leak on my passenger's side that I couldn't close up. I finally went with Remflex crush gaskets and that sealed it up.

 

[Black*Death]

If you have stock parts then slowly bring back to stock and see if that helps. Should not be too tough to change CAI and TB. I think it is a combo of things...

I know on the S197 Mustangs you have to get a retune with the vast majority of CAI's..car leans out if you don't.

I thought rear O2 sensor issues would affect driveabilty? Not sure if they affect idle though? Maybe somebody with tuning experience will chime in here?

 

[poneypower]

I ran my Densecharger CAI with stock TB and stock exhaust for two years with no tune and no problems at first. The only thing I started having were issues with a bad idle due to the CAI not staying together. The filter kept coming off, causing the car to want to stall. I cranked that clamp down to the point right before it breaks.

You need to run MIL eliminators with the O/R pipe, otherwise you're always going to have the check engine light on. They run like $60. A handheld tuner has the ability to turn the rear O2s off as well.

I would definitely start by checking for leaks in the CAI or around the TB, it doesn't take much to cause a problem. Clean out the sensors too. MAF, IAC etc like SilverNotch said. I found some oil buildup on my MAF due to the oil in the filter.

 

[01yellercobra]

When you swapped out the throttle body did you reset the TPS? Most throttle bodies for our cars are known to have issues. That's why they're not a popular mod for us. I'd try the stock TB first.

The rear O2's don't do anything for driveability or the A/F. They're just there to make sure the cats are working.

 

[nasty99]

Thanks a lot for the great advice guys I'm new to this and can really use this help. I bought the car with the tb already installed. The previous owner said it ran great. However he didn't have the jlt on it when I bought It I put that on myself. That also goes for the exhaust setup. It seems like after the exhaust was put on it started messing with the idle. And then I put my cai on in spring of '10 and it didn't make it better of course. And the other day my mechanic fixed my exhaust leak, and NOW its also starting to stutter and buck when my foot is light on the gas pedal. (Similar problem was jus posted a few days ago in this same forum). But anyways keep the input comin guys I appreciate it. Sorry for the long response. I just want this car to run right and I won't have to keep makin posts about a broken cobra every other day. Its been breaking my bank the past couple months I've been so frustrated.