I am not sure if this is a tune issue, or something such as a bad MAF ect;

As purchased the black car (see sig below) was tuned, but the car was in sorry shape;
I spent several months putting the car back to stock with one exception - it had GMS1 map sensors installed, so when I was done, I put a GMS1 tune that I had saved some time prior from the HPT tuner repository.

The only other items which deviate the car from 100% stock, are:
Drop-in K&N filter (the one I ran before getting a CAI;
A loud muffler (the yellow car has the original exhaust and a catless downpipe, and for regular driving, it's quieter than the black car).

As it sits now, the car drives runs and drives fine, and other than the odd noise that I haven't been able to identify (CAB's?) - it's been rock solid reliable.

All that aside, 99% of the time the idle when coming to a stop in traffic is way too high;
We have typically been able to get it to idle down by putting on the rear defog - presumably this is putting a little load on the engine via the alternator, and the additional load masks the issue.
The fact that on occasion the idle is fine (meaning not too high) makes me think that this might be a sensor and not tune related.

I would really like to find the cause of the high idle, and was hoping someone here can help me out.

I have a Tech2, as well has HPT.

BTW, any leads on an undamaged rear, drivers side door panel for an SS-sedan would be appreciated.

 

Double check the idle tables in HPTuners, it's possible someone tweeked them before uploading to the repository and didn't notice it.

I'll try to remember to get my tuning laptop out and double check the stock idle numbers and then get back on here to update what stock values are. Not on here much anymore since the balt got totalled just over a year ago.

 

Additional thought after hitting post, do you have a boost leak tester and/or a smoke tester?

 

I do not have a leak tester, but I could look into that.

If it was a leak, I would think that creating load on the alternator shouldn't kick the idle down...

I figured that maybe I needed to look at the tables, or look at a faulty component.

I cannot recall what tunes I backed up from my personal car, but unfortunately I think most of my personal backup are trifecta tunes;
If worse comes to worse, I may be able to revert to a stock tune on the yellow car, back that up, and use that as the base tune for the black car.

Thanks for the replies - and sorry to hear your car was wrecked.
I only know one local who still has his car - and I pretty much never hear from him (I haven't seen him in somewhere approaching ten years now).