Schlitz03gt

Hey everyone, I have been searching thread after thread looking for a soltuion to my idle problem but i am still at a loss as to what it may be. I have a 2003 5spd GT that has 95k on the odo, pypes catted X, Magnaflow mufflers, BBK 75mm TB, Volant CAI, and a Diablo Pred Tune. MY problem is at idle my rpms fluctuate from 900 to 400. this in turn makes the engine run a bit rough as you could imagine. when im driving the problem is gone and i see no jump in my driving rpms. I have replaced the spark plugs with OEM Ford Motorcraft, but i have the same problem. The only 2 things i could think of is maybe i have a coil going bad, or a possible IAC problem based on what i have read so far. I have ran multiple tanks of gas thinking that would be the problem but no change. any suggestions or help would be greatly appreciated.


Thanks
Josh

Sxynerd

IAC, or vacuum leak or if your symptoms are a little different then your description, your Decay Rate is screwed up from the A/M stuff.

black35th

+1

Welcome to the forums and THANK YOU for at least trying to use the search function before posting a new thread, your one step ahead of the rest.

mustangman281

What was the last mod you did before this started to happen?

Schlitz03gt

My Last mod was the Pred Tune, but that was done last summer, and i just recently started having trouble within the last month, so thats how I ruled out my mods (not saying they arent causing it, but just made sense to me). I'm going down to NAPA this morning and will purchase a new IAC, I hope this will fix the problem, i will also look into my hoses and replace if needed. Thanks for the replies everyone, I will post an update later this afternoon.

thanks
Josh

Dan04COBRA

Canned tune or was it dyno tuned?

Check for vacuum leaks, clean your IAC or replace (highly recommend replacing over cleaning) and check your TPS. Consider loading your factory tune and see what happens.

Dan04COBRA

Canned tune or was it dyno tuned?

Check for vacuum leaks, clean your IAC or replace (highly recommend replacing over cleaning) and check your TPS. Consider loading your factory tune and see what happens.

Schlitz03gt

Im using the can tune from diablo. I went ahead and replaced my IAC and that did the trick. Thanks so much for everyones help. I really appreciate the quick replies. part ended up costing $56 with tax at advanced.