my throttle position sensor recently went out and replaced that. Then I had 4 other codes I had to fix. Fixed all of those as well. Well the last one I fixed was for a o2 sensor code. Now another code came up and its p0300. Fuel pressure is good, cap and rotor replaced as well as plugs and wires. My blazer still backfires a lot and the mpg seems to be pretty bad. My fuel trim readings seemed to be off I think? This is how they go:


STFT Bank 1: 50
LTFT Bank 1: 7.8
STFT Bank 2: 3.1
LTFT Bank 2: 7.8


That first one seems to be way higher than the other three. I guess this isn't right? You think the other o2 sensor before the cat needs replaced? I replaced the driver side o2 sensor. I need help guys, I need this bad boy 100 percent so I can have him for the coming up snowstorm. I cant miss work!!!

 

try cleaning out the mass air flow sensor. that seems to fix a bunch of problems on these trucks.

 

You may want to pull the distributor and have a look at the gear.
It could be worn.

Is that a typo for bank 1 STFT??
Your fuel trims are fine.

 

Your long term numbers show it's running a bit lean on both banks. Short term on bank 2, (cyls 2, 4, & 6 passenger side) is nearly perfect, while short term on bank 1 indicates the PCM has maxed out trying to richen the mixture. Could be a clogged injector, (or poppet if equipped), valve not closing or opening properly, etc. Bottom line is: too much air and/or not enough fuel on bank 1. Which eliminates secondary ignition and all sensors as being the problem.