97 z28 lt1 OK I had my PCM sent to swaplt1 to delete emissions o2 sensors evap egr ect I got it back drove it couple weeks no problems and now I have code p0171 p0174 running lean so my question is does it has to do whit the delete of everything? Or should I check the maf sensor and fuel pressure? Or a quick fix just to pass emissions need to have it done by October 31 help please!!

 

As long as the pre-cat O2 sensors are functioning correctly, this is not related to programming the emissions out of the PCM. But, did you correctly block all vacuum connections related to EGR and EVAP? Did you correctly block the EGR and AIR connections to the exhaust?

 

Yes everything is block the right way I just found out my mecanic check the gas pressure and is low will that be the problem?

 

Low fuel pressure will cause it to run lean.