I have posted in other threads about fixing other issues with my 05 Cobalt SS Supercharged I just bought. 1st gear builds no boost at all. Very slow 1st. My 2nd gear still accelerates slowly and then around 6k rpm it starts to build 15-17 psi at once and it gives a good butt dyno then falls on its face because I have to shift at 7k. 0-60 feels like 11 secs. I never really had a chance to really push it because it wasn't registered and was at dealership for 2 weeks. Just now discovering this issue. While it is taking off it sputters many times during a hard pull but in quick succession. I pulled only 1 Code which is causing a check engine light for P0502: Vehicle Speed Sensor (VSS) Circuit Low Voltage. I heard from another mechanic that Cobalts with a check engine light may run limp. I really want to upgrade the car to TVS soon but it is not running right by itself.

 

Well I'm going to go out on a limb and say the VSS issue is causing all of it, if the ecu can't determine the speed it's going to put it into a power reduced mode, which should be popping up on your dash.

Is the car tuned? What pulley do you have? What additional mods are on the car?

 

The guy I got it from says it's was tuned with a Cobb tuner. It has a zzp 3 inch pulley and cat delete code since it has full exhaust. Also Exedy Clutch.

 

I'm fairly certain Cobb doesn't have any cobalt products.

I would start with getting the VSS fixed and then buy hptuners since you plan on going TVS at some point, download the file on the car and then log the car while driving.

 

I can guarantee Cobb doesn't make anything for the Cobalt.

 

I just bought the VSS from Autozone. Now got to figure out how to get it on. Also the car has no codes for no catalytic converter. So some kinda tune has been done.

 

Might be trifecta or hptuners