Mustang Stalling with Diablo Performance Tune

[tonygug]

I have a 2003 Mustang V6 3.8L with a Pypes Performance Complete Converter-Back Dual Exhaust, a K & N cold air intake and Hardcore 8mm 0-ohm wires set. After I installed the predator performance tune the engine (50 % of the time) dies when pulling to a stop. I have Predator model U7146. I modified the tune and brought the Idle RPM to 870 for the mean time, but I'm not sure if that was the correct thing to do. Do you know what is wrong?

[mikel]

It is likely an issue with the CAI.
Try removing it to see if it goes away, or look into a custom tune to work with the CAI.

Thanks

[tonygug]

I don’t have the original CAI to put back on. Will it hurt my car to raise the Idle RPM, which seems to have stopped the problem? If so, how do I get a custom tune?

[mikel]

Raising the idle will not hurt anything.

Thanks

[tonygug]

Does that mean that the performance tune (and raising the Idle) is the best for my car or should I get a custom tune?

Thanks

[mikel]

You should not need a custom tune.

Thanks

[tonygug]

So, is using the performance tune and raising the Idle my best option?

Thanks

[mikel]

Yes.

[LightningMike03]

Look for a vacuum leak.

Your car is getting old enough that the rubber lines will be starting to deteriorate and since you have recently installed the CAI some of the lines around that may have cracked in the installation process.

Idle speed and vacuum are closely related. As the idle comes down, vacuum rises and if there is a leak it will not raise high enough fast enough and the engine may die.

A good A/F gauge would help in diagnosing this issue. Knowing how quickly and how much vacuum your engine pulls when coming down to an idle is something that you should know. The A/F gauge will tell you if something has changed in that regard.

[tonygug]

I apologize for my ignorance but I am new to car mechanics. I decided to add some bolt-ons to get better performance out of my car. When I installed the CAI, I replace everything up to the throttle body. So I’m not sure which rubber lines you are referring to. Could you please explain, I would like to learn?



Thanks for the advice; I will look into an A/F gauge.