2009 Chevy Cobalt SS

Two things happening:
1. When I'm holding speed, either on cruise control or just low throttle input, the turbo does it's soft whistle discharge in rapid succession. The discharge is normal, but should not happen over and over again rapidly while maintaining speed.

2. Randomly, my car will start and run normally but won't build any power and then when I let off the gas the turbo will discharge in a rough fluttery sound. It randomly stops doing that also.

I wonder if there is a valve that is getting stuck open/shut. I'm sort of lost.

 

The 1 point is normal on these cars when tuned and I'm sure semi normal for a stock tune.

Point 2 check for boost leaks.

 

What mods do you have? Gms1 tmap has a tendency of doing this if it isn't soldered properly. Or if an intake is theowing of your fuel trims badly.

 

I have K&N typhoon intake and the GMS1

 

Super common problem. Most common issue is lower map sensor harness is rubbing on fan shroud or getting oil residue from an over oiled filter. I can't say for sure which problem I had 100% but replacing the lower tmap and guiding the wires away from the fan a bit stopped the issue. Or at least stopped throwing a cel in my case. I also think the dealership may have used the wrong o ring when they installed the sensor.
I made a point to grind the excess tab off on my new one and and grease the o ring for a peopper seal.

 

Are you getting a cel? I was getting p2178. And searching at the time showed allot of gms1 cars with the issue many of them K&N sri equipped. Some found it was just. Abad sensor.

 

I had the same isssue. Mine was the lower sensor. Pulled it out, cleaned it and popped it back in and good as new

 

Check map, but before that cause it's hardest of the 2, bypass ur bpv solenoid and hook bpv.straight to intake manifold. If that fixes it, buy new solinoid or just leave it bypassed. When bypassing , make sure u run the line u unplug from intake manifold up to where u pull the bpv line from on the solenoid or u will have a boost leak

 

Thanks to everyone who commented. I used some MAF cleaner and the CEL went away.