Wasn't sure where to put this so if it needs to be moved. My car is stock but I do have full bolt on's. Stock turbo also. I just loaded the Cobb AP with the Stage 3 tune v4.03 and just noticed this issue. AFR's seem to be erratic. At cruise they bounce from 14.2 to 15.5 constantly with a steady throttle position but every once in a while they go lean and then bounce back up. At idle (about 800 rpm's) it will sit fine for a minute or two then bounce down like it wants to stall then back up. AFR's go lean also when this happens. If I am rolling at all, such as in neutral, clutch out and just rolling a little it won't happen and idle is about 1100 rpm's. As soon as I stop completely, idle will drop to 800, be fine for a few seconds then become erratic.

Car is a 2008 with 107k miles. Like I said, full bolt on's including TBE 3", Injen intake, EBCS, 25lb. waste gate actuator, turbosmart bpv, headers, and fuel system upgrade. No injectors yet but DW300 pump, Boomba rail, AEM regulator at about 48 psi at idle. Haven't logged any info with the AP yet but will soon. WOT pulls seem smooth and AFR's are 11.5 to about 12.2 (also kinda bouncy, not steady).

Any advice or recommendations anyone could provide would be appreciated.

 

What happens if you put the stock tune back on? If it does the same then i would look for boost leak or exhaust leak.

 

No change when I go back to stock. Still does it. I am going to look for boost leaks and such anyway, just to be on the safe side.

 

The roll to stop issue you describe happens to me on stock tune, e tune and my current tune. I'd say it's normal.

The fluctuation you describe at cruise is pretty normal also.

The stalling or ear stalling issue is not normal. You need your tuner to look at it. There is a few things that could cause that.

 

had the same problem on my stage 1 test map that cobb sent me when trying to fix a different issue. told them about it, looked for the leaks they told me to look for and they ended up sending me another tune that fixed the idle problem. car doesnt seem to pull as hard but its making more boost (25 psi) now with the test 2 map vs test 1 map that made about 24psi...

 

The same exact issue happens in my car, mostly stock. The rpms flutter and the engine almost wants to die often times. One time it was a case of bad gas, once I got good gas it in the problem went away. Other times it happens I cannot narrow it down. I am thinking the problem is in the tune. Whether I run AP OTS maps or stock, I still experience the problem. I think it is a issue a good tuner can tune out.

 

clean the maf sensor? Made a world of difference for me.

 

Sure did! And cleaned the whole intake system and changed the plugs. Still there.

 

Maybe check this hose:

https://www.evolutionm.net/forums/ev...s-do-asap.html