I could use some advice with my 08 S.S.

the other morning out of nowhere, the C.E.L. came on along with a serious loss of power, boost guage showing 1 or 2 pounds at full throttle. I pulled over, shut it off while I checked under the hood...started it back up and it was fine for about 2 miles, then the same problem...I got home (seriously underpowered but no skip or hesitation) I disconnected the battery for about an hour. Hooked it back up, C.E.L. is out and boost is back up to 22psi and has been fine for 2 days. WTH?? Can I expect this to be a re-occuring problem? Anyone else have this issue? Thanks for any advice.

 

Sounds a lot like a chafed or loose wire. Should have got the code read and the freeze frame, all of that goes away when you clear it.

 

I do have a friend who will scan the car for the code if it happens again. He suggested a bad boost solenoid but the problem isnt constant. Gotta pay to play I guess.

 

Would be nice to have the code...but if you are boosting 22 you must have stg-1, and if you didn't hold the sensor back from the condenser, I think Don is right, lower Tmap sensor or the wire.

 

THANK YOU VERY MUCH!! The problem has not reared its ugly head again which is very strange. Ive lost a little bit of confidence in the car but I do appreciate the advice.

 

My HHR with the GMTU was falling flat on its face with zero boost almost everyday a while back. I completely lost my trust in the car to get me to work and back home everyday. I had been so focused on the known lower MAP sensor issues (crimp connectors and hitting A/C compressor) that I forgot to check the upper MAP sensor wiring. When I did, I found these crimp connectors (with TWO nasty connectors on what happened to be the 5V source wire). I cut out the connectors, soldered and shrink wrapped the wires, and haven't had a boost problem for 1000 miles! I FINALLY have my confidence in the car once again...knock on wood.

 

Good to hear you found the problem Rlee

Radio Flyer as everyone mentioned check upper and lower wires.

I highly recommend turning the lower tmap 180 degrees.
that was one issue I had but the one that seemed to keep coming back until I had the pcv valve changed was the upper tmap sensor would get alot of oil on it and that was causing my issue.
IF i cleaned it every three days i had no problems now that the intake and the pcv was changed its been great.
I know the next time I have a boost issue I will clean and replace upper and lower tmap sensor.
Really in the long run I think the Powell pcv system is the way to go to prevent a lot of these issues that are not electrically related.

 

Thanks, bigjacksauto. Over 1200 miles and counting without a boost issue. Can't wait for the PCV value issue to rear its ugly head, but so far so good...