cobalt_sport08

iTrader: (1)

Hi everyone!

I picked me up another balt 2009 SS with 150k. I'm going to do my best to read the forums again and diagnose my own problems. But I do have some questions.

I got the car with come CELs (P0013,P0014,P0128,P2178,P0114) so I went and changed out both intake and exhaust solenoids. And did an oil change to Mobil 1 full synthetic.

Prior to doing this the car under WOT would hit 22-24psi and felt very responsive. Now after making the fixes car makes 15psi and feels sluggish. New codes are P0128 and P2178.

Should I be concerned about the thermostat because the coolant has been anywhere near or above 190 degrees. And why would I be running rich now? AND last but not least would an exhaust solenoid make the car over boost?

Thanks in advance ​​​

ECaulk

iTrader: (6)

The P0128 points to a stuck open t-stat, and that is sort of confirmed by your comment about the temps not getting near 190.

The P2178 could be related to the P0114 you previously had. The solenoid replacement didn't change the rich condition, as your post indicates you had the same code prior to replacing the solenoids. I'm assuming you reset the codes after replacing the solenoids. The MAF could be going bad or just a poorly made MAF, IIRC @ProfDNS had a similar issue with the running rich on a non ACDelco MAF that was corrected when he replaced the MAF with an ACDelco MAF. You could try disconnecting the MAF and see if the car runs better, don't try to go WOT with the MAF disconnected just some part throttle to see if the car accelerates better.

cobalt_sport08

iTrader: (1)

Yeah I cleared the codes after changing everything. The P0128 and P02178 came back almost immediately. Should I be concerned about the open T-stat?? I mean living in Florida we get some hot summers so I wouldn't see a problem with the car running cooler in traffic...

Now if I pull the MAF what would make it run better?


thanks

ECaulk

iTrader: (6)

I would put replacing the t-stat on the list, but I would solve the P2178.

If the car runs better when you unplug (don't remove) the MAF, then it points to a bad MAF or bad MAF signal. I haven't looked at the cost of the ACDelco MAF recently, but if it's cheap enough it's not a bad idea to have one on hand.