I just installed new vette Bosch O2 sensors in my Z-28 last night, the code went away but now the car stumbles and want's to die. Before it was running really rich but ran fairly well considering the O2's weren't reading correctly, now it's acting like it's getting either too much fuel or not enough. Last night at the Sonic it stumbled and started missing really bad so I had to feather the gas to keep it running, once it straightened out I opened it up to burn all the fuel off and it ran great after that. This morning it decided to do the same thing again. I ran the codes at autozone and it said I was getting a mass air frequency low and high. Would that cause it to stumble and run like crap? On top of this my A/C compressor took a **** on me last night, thought the motor blew up the way it was sounding. I heard this loud knocking sound after I left the Sonic, luckily it was just the compressor bearing going bad.

It's always something! Any thoughts on what to look for would be great. I'm going to clean the mass air sensor again tonight with some electrical cleaner to see if that helps.

 

it almost sounds like your egr valve is bad in it but the code scanner should have picked that up. Does it feel like it is skipping, and like the car is being held back?