Power Loss, Bad Mpg, Weird Shifting

[00YukonSLT5.3Rwd]

Well I put good gas in my Yukon and it was still pinging. So I hooked my scanner up and started doing tests. I tested the MAF sensor and it was reading properly. Fuel pressure seemed good, throttle sensor reading properly. Temperature was right. O2 sensors normal. Then I got to the MAP sensor and it was a little off. So I headed down to my parts store and picked up the good MAP sensor, ran me $52 at cost. I pulled the old one off, snapped in the new one and drove home. The ping is gone, the throttle response has returned and the shifting is smooth. I looked at the scanner and now it is reading within parameters.

 

[shaunt23]

wow that worked... good for you

 

[00YukonSLT5.3Rwd]

I probably should have taken the time in the beginning and went through all the checks but I didn't have my scan tool back from a friend for a while. Assuming the problem would be fixed with the knock sensors... well we know what assume means. I hope you get yours figured out. If you haven't done the MAP sensor, have it checked. Absolute pressure should be between 10 and 30 inhg at idle and mine was reading 7.8. After replacement it now reads 10.8.