I don't frequent as much here since I purchased a G8 GT earlier this year but I have what I think is a tuning related question. 06 LSJ, 60's, 2.9 pulley, dual pass, zzp HE, full ZZP 2.5" exhaust, etc. Anyway, I had my car dyno tuned about 30k miles ago (spring of last year I believe) and it ran/runs great for the most part with the exception of an idle hunting issue. When I first got it tuned, since it was spring, the outside temps weren't that high. When it got to summer I did notice that every once in a while the car would hunt/surge around for the correct idle speed when coming to a stop. Nothing crazy and usually a couple ups and downs and it would correct itself. If it wouldn't, a quick blip of the throttle would fix it. Now this summer I've noticed that it seems to be doing it more frequently. It does it more when it's really hot and humid out. I can watch my wideband when it does it and it follows the hunting idle by going really lean to really rich. I don't have anyway to data log but I'm just curious if anyone has experience with a similar issue. It hasn't gotten to the point that I feel I must fix it but it is annoying when I pull up to a light and it's doing it. Sorry for the long post and thanks for any assistance. Oh, I do know there have been issues with 60's and idle.

 

And the maf gets cleaned reqularly along with the throttle body.

 

My idle is absolutely garbage and it is all in the tune. It's definitely possible you have nothing wrong physically with your car and the tune just isn't dialed with the effect being multiplied with high ambient temperatures.

 

Also, tunes dont just "go bad". it sounds like as HGT said, they didn't take the car out and tune it on the street after dyno tuning. most good shops know to do this.

 

He said it's always had an idle hunt issue since he got it tuned. Ambient temperature extremes can definitely intensify the symptoms depending on what part of the tune is actually causing the issue.

 

We are all aware of your tuning prowess

 

I dont know much about cobalt tuning. but I do know that they have MAF Comp temp tables to fix the swings in temps. Maybe the shop didn't fix that?

 

I don't know, I just know with my Trifecta experience that my car doesn't like to idle sometimes because of the tune. I know it's the tune because I can smooth it out by manipulating the throttle. It starts to swing and doesn't like to stop. Temperature extremes can change the intensity of the effect. I don't know what it would take to correct this issue but Trifecta can't seem to figure it out for me. It's very annoying. Stop lights are embarrassing for me.

 

ah, The only tuning I did was on my 08 SS LNF so I dont know about the other ones. JD has to use Trifecta. ugh

 

It sucks. I want to go standalone but don't know where to to get started. Not being able to get my idle tune dialed, not to mention the extreme rev hang, really annoys me.

 

Start by buying a standalone

 

 

AEM seems like a good start. buy that one

 

Just buy the first standalone ECU that shows up on google?

 

I'd kind of like to have a plan from start to finish before I start buying stuff. I don't think this is one of those things you want to go into ass first.

 

Yes, but the ECaulk stand alone, and you'll be standing alone all the time

 

 

I didn't notice the idle issue until months after the initial tune since it didn't present itself until the heat of summer. That was last year and it annoyed me a little but now it seems to be getting worse/more frequent. I didn't have the greatest experience with the shop so I don't know that I'd want to go back there. They supposedly road tuned it as well. There is someone local that road tunes. I think ecoboost's and mazdaspeed's mainly but dabbles in others. I may look into him at some point. I just wanted to get some feedback as to whether yes it could be the tune or maybe other mechanical places to check. I do have a scangauge, should I set that to monitor STFT? I don't know what numbers I'm looking for exactly.

I also don't think I've ever really posted a picture of my car. Got it bone stock at 133k. At 176k now.

 

Honestly checking mechanical health is always a good idea, I'd start with checking for any vacuum leaks and get a leak down test performed. How old are you spark plugs and your oxygen sensors?

 

Spark plugs were changed at 170k (NGK one step colder). O2 sensors are Front at 133k and rear at 157k with OEM ones. Air filter cleaned with MAF at 174k. Fuel Filter at 157k (could probably stand to change that again). Fuel pump changed at 135k. MAP sensor at 148k. Crank position sensor at 145k.

I maintain the car pretty religously since it was my baby before getting the G8. I've rebuilt the whole suspension, swapped out the few vaccuum lines it does have, changed the timing chain, balance chain, tensioner, added head studs, changed the supercharger coupler and added new oil, etc. I know most of that has nothing to do with the problem but just an idea of how I've maintained it. Oil gets changed regularly around 4k miles also.

 

And thanks for the help so far guys.

 

Idle issues aside I like your Cobalt. Very clean

 

Then I would get a leak down test performed and verify you have no vacuum leaks. If those both check out it's likely tune related.

 

Thanks. It has been a pretty good car to me especially since I drive it pretty hard. It has always reminded me of my old 92 Sentra Se-R but with a supercharger.

 

I stated in my original post that I do. When the idle goes weird I can watch it go rich to lean with the up and down of the idle.