CGifford

So i had the 0089 code on my 2009 Cobalt SS but it was running fine. I saw in another thread that a couple people cleared the code and it never came back. After doing this it would start and then just stall out. Just trying things i ended up unplugging the mass air sensor and the car would stay running. Any suggestions cause i am in over my head with this dual fuel pump set up. Thanks

steelmesh

I see you've been browsing P0089 code postings on this forum already. Looking through a few of those looks like the code is set because the fuel pressure is outside the expected window of operation. I don't have access to the diagnosis steps, but my wild ass guess is to monitor fuel pressure through the computer scanner and compare that against a specification.

CGifford

Thanks Steelmesh, I think because i cleared a base code that was the original problem my car has gone into limp mode. I was told to change the mass air since that was my first code from a long time ago and it might straighten out the fuel pressure issue since the computer will start getting the correct sensor readings.

ProfDNS

I had a similar issue a couple months ago, and it was the MAF being dirty (I cleaned the MAP as well). When you first turn it on, press the gas pedal enough to get the revs up then slowly back off. If it does or nearly dies, you're running way too lean.