Lurker finally raises his hand for P0171

[icetherice]

I have cleaned the MAF twice...I think it's skewed due to its age, and will probably be putting a new MAF sensor in today. It was heavily contaminated when I first cleaned it and I used a qtip in addition to the cleaner so I may have damaged it

I have not checked the TPS sweep for glitches but I will try that before I purchase the MAF.

Hmmm...exhaust exiting a catalytic converter should primarily be co2 and h2o...so where is all that oxygen coming from...

I went around the exhaust with muffler putty and sealed the leaks that I found with a smoke tester I built the other day..didn't seem to change anything.

(I know, I wish they would stay in columns like they do when I paste the data in because it's easily readable then...I think the forum backend deletes additional white space)

 

[icetherice]

Checked TPS: good sweep from .9v - 4.5v

 

[RonD]

Yes, O2 sensor 2's should run steady at .7 to .8volts which is low oxygen levels, "Rich" on an O2 sensor 1

Not sure why you are getting 0.0xx on sensor 2, then it switches to 0.xx
Maybe a glitch in the reader?

Original O2s read(generate) .1 to .9 volts, .1 being lean(high oxygen levels) and .9 being rich(low oxygen levels)

Newer Wide band O2s read 0 to 5volts

 

[icetherice]

I replaced the MAF sensor and the fuel trims began returning to normal. There was also much less rev-hang during open loop. I expect the P0171 code to disappear on my drive to work tomorrow.

My o2-2 sensor still registers intermittently. Most of the time it's flatlined at like 5mV. I will evaluate whether or not to replace it after P0171 clears..because I can only imagine that a trace that low will set a code such as P0140.