New member.
1997 blazer 4.3, 4-wheel drive. SES light on with codes P0171, P0174.
Have cleaned the MAF, installed new air filter(stock, not oiled), no vacuum leaks, new fuel filter, new engine coolant temperature sensor, cleaned IAC valve. cleaned throttle body, no exhaust leaks. Have sprayed starting fluid around upper plenum and around lower intake manifold gasket area (old trick), but idle did not change. Car idles rough in gear and will eventually stall. Any more ideas? Great site by the way. I have read many posts on this, but I still have not solved this issue.

 

How does it run with the MAF sensor unplugged?

Have you stepped down through the diagnosis of those two codes?

 

Thanks for the reply, I unplugged the MAF with engine running and it cut off instantly. Is there a way to check the MAF?

 

Do not unplug it with the engine running. Start the engine once it is unplugged and see if it runs better or the same. It will throw a code for the MAF sensor.

 

Thanks will check that tomorrow. Raining here right now.

 

Update: Pulled out MAF again tonight and cleaned again. Noticed corrosion all inside of the hose making a bad connection. Cleaned all corrosion out of hose and off of MAF sensor body, Installed in car and cranked it up. SES Light went off instantly. Hopefully this problem is solved.