So i just bought a 09 ss on Friday.
Drove great the first 30 min or so, then no boost.
Found that problem, whoever had the car before me did some redneck engineering on the lower charge piping, that came apart as soon as i got into boost, i was able to fix that issue today and it seemed to work fine.
However, my problem now is that if i get on the gas right when i start the car up it boosts no issue, after the first time it spools up it wont do it again. Cant get above 1psi after that first spool, anyone have any ideas what my problem is.

 

No CELs? I would inspect the charge pipes thoroughly and also the intercooler. If it is stock it had plastic endtanks which have been known to break if you hit a deep pothole too hard or curb.

 

Initially it threw a P0299 code, got that cleared at fixed when i "fixed" the lower charge pipe but its still not right.
Upon further investigation when the previous owner did this he removed the portion of pipe that the lower MAP sensor attaches to, so therefore there isnt a lower MAP sensor any more. Which in turn keeps throwing the P0299 code and putting the car into limp mode.
I bought the car from somewhat of a less that reputable place so hopefully they will fix the issue.

 

That's probably why you can't boost, need both maps for the car to read levels

 

Okay thats pretty wierd. Take a pic of the setup you have and post it. The only modifications I can remember that have been done to sensors is the MAF relocation so that an atmospheric BOV can be run. The MAF is moved to the lower charge pipe. Treadstone made those. They dont seem to make anything for cobalts now though.

The other one was tuning based on atmospheric pressure and eliminating the MAF (not physically removing it but removing its function).

Oh there is one more. The lower TMAP sensor is moved on the lower charge pipe and a nozzle is installed for methanol injection. Again, another Treadstone item.