Idling problems

[bdp55]

Hey guys, I have a 2000GT, it idles really rough, when I start it up it is fine until it gets to running temp, then it goes crazy, it almost dies and then it revs itself up to about 1500rpm, it does this back and forth until it finally dies, The Throttle adj seems to be okay, and I haven't done any major upgrade for a while, this just started, any ideas on what it could be?

 

[Kilgore Trout]

I think primarily it is low on freon and needs some general preventitive maintenance like being SeaFoamed all three ways, cleaned IAC and MAF, and reset PCM.

 

[Outlaw97GT]

You might wanna check out your TPS also.

+1 On what Trout said too.

 

[Kilgore Trout]

Oh yeah, TPS... That's probably the problem, did not think of that.

 

[Keldog]

I think primarily it is low on freon and needs some general preventitive maintenance like being SeaFoamed all three ways, cleaned IAC and MAF, and reset PCM.

What in the world could a vehicle being low on freon possibly have to do with why a vehicle's idle is rough and dying? That can cause the compressor to kick on and off but it shouldn't cause the vehicle to shut off. Cleaning the throttle body, IAC and MAF can possibly fix it but I would also check to make sure you haven't had a vacuum line or other intake hose possibly work itself loose. At a higher rpm the engine will run smoother as vacuum increases but at a lower rpm like 800 or lower escaping air can cause a rough idle condition. Since you didn't mention your check engine light coming on or loss of performance my guess would be an intake leak of some sort.

 

[Kilgore Trout]

Low freon cause the idle to fluctuate. Combine this with dirty IAC and it will cause the problem descibed.

Anyways, it is probably the TPS.

If I am wrong I will give him his money back

 

[Keldog]

tps is a good point. I would just eliminate the simple stuff before adjusting or replacing anything. I work for an auto parts place and I see so many people who ignore this point before laying down hard cash.

 

[bdp55]

what else?

Okay guys, I took it to my shop that tuned my car previously and they can't figure out what it is either, he's cleaned all the sensors, even tried replacing most of them (TPS, MAF....) but but the problem won't go away, he said he can't find a vacuum leak either? Any other ideas?

 

[SilverBullet00]

I have a similar issue. What mods are you running?

 

[bdp55]

I have a similar issue. What mods are you running?

I've got a procharger with a D1 head at 10lbs of boost, 75mm T/B, 75mm plenum, intake spacer, BBK shorty headers, x-pipe, flowmaster prochamber exhaust....and others that don't effect the motor like shifter, suspension....
The guy working on it took it to a ford dealer to have them run a diagnostic and they said that every cylinder is mis-firing, both at idle and under load...there are brand new spark plugs, coils, injectors...they did a compression test and everything checked out. They cleaned all the sensors, nothing. They can't find a vacuum leak or anything like that, the dealer thinks it's an electrical issue? All I know is I'm getting screwed with a huge bill when they don't even know the problem yet. Also my car use to make about 410 rwhp, but now since this happened it only makes about 330 rwhp. I just hope they figure it out soon!