Strange stalling issue

[scupking]

Ever since I had the Mac LTs and VRS catted X pipe put on my car she will start with no issue idle with no issue but as soon as I put her in R or D she will stall. If I let her warm up for a few minutes she wont stall. After driving then turning the car off then going back to drive her after a few minutes she will start but then on the idle down the rpms will go down to like 200 jump to 1500 then back down to 200 then back up to 1500. If I give her a few quick revs she will usually idle back to 800 RPM. I'm thinking my idle might be set to low for the cams. I have the idle set at 800 in neutral/park and 850 in drive. I'm going to change the Idle to 850 at idle and 950 when in drive to see if this stops the stalling problem. If I hold the gas peddle down just a little it won't stall. I don't think its my IAC seeing as I had that issue a few years back and replaced it. What do you guys think?

 

[GDTrumbo]

With the addition of the LT's, the upstream O2's bung location is significantly farther downstream than with the OEM manifolds so it takes longer for them to receive/send signals to the ECM. I have read about this issue and its effects many times.

GT

 

[navarro98gt]

I had that problem after installing cams. It took me three different tuners before I found one that spent the time and had the knowledge to fix the idle issues. So my guess is that it’s a tuning problem.

 

[Stark77]

Tune for sure. I had a 2 week gap between installing LT's and getting the tune, had the same prob as you (it's specific to automatics, I believe). As soon as I got a fresh tune, issue was fixed. Checking the IAC may not be a bad idea either.

 

[scupking]

I had a dyno tune last Friday but the car was not doing it so he couldn't tune for the issue. He did say he would try and email me tunes until we can get it figured out.