1994 4.0 Running Bad

[PKH]

Hi hope you guess can help. Went to the car wash and things went bad within a half of mile, missing not power shut of, backfiring the works!! I don,t like to be a parts changer but now I am. New coilpack, New IAC, New left hand Ox sensor, New reman MAF. fuel pressure good all the time, last code I got was 126, so changed left hand ox sensor, didn,t help at all last night I unpluged the MAF and it runs great, did the voltage check on the MAF and it ck,ed good as best I could tell, put new MAF in today didn,t help at all. After work I will pull the codes again, other than that don,t have a clue. Could use some help!!

 

[alwaysFlOoReD]

Unplugging the maf forces the pcm into closed [or is it open?] loop, almost like a limp home mode. That is the pcm ignores the sensors and runs on a pre-programmed fuel and timing map. So that means it is not necesarily the maf that is bad but another sensor. Once you pull codes again hopefully someone else with better knowledge than I have will chime in.
Good luck,

Richard