UM Rebel

I have a problem with my 2004 Suburban I hope someone can help with. It runs really bad, no power, clatters and backfires will hardly go over 45. CEL is on and sometime flashing. Autozone read codes P0101 - Mass Air Flow (MAF) Circuit Range/Performance Problem
P0300 - Random misfire

Changed MAF with my Corvette. Corvette still runs fine (no codes). Suburban still runs bad. Checked cats temp front (300 degrees) , back (500 degrees). Checked fuel pressure at 45psi . When I blip throttle jumps to about 50. From what I've seen fuel pressure should be a little higher. Where do I go from here? What do y'all think is going on? Thanks for any help and advice. BTW is 2WD with 5.3l non Flex fuel engine.

skycries57

went through same on mine, cleaned maf sensor and went back to norm. same on my toyota sienna. could b bad coil or plugs. if its been a while since replacement on coils and plugs, its a cheap fix, betcha it will fix it, did mine and others i know of when these issues come up.

cleveland63b

your corvette probably has different calibrations I wouldn't count that as an accurate test for anything, I would also start with cleaning the MAF and see if it changes anything, do you have access to a scanner at all? Start with the p0101 it may be the same root cause for the p0300