Just as the title says, I made a log 3 weeks ago and everything is fine, go out of town and now my logs have the O2 mv fluctating as if they arent even in PE mode (they osscilate up and down in the datamaster graph). I have tried loading different tunes and nothing seems to work. Its almost as if my computer doesnt recognize the car at 100% TPS and doesnt enter PE mode (even though datamaster shows 100% TPS-4.51v) No changes have been made, and I checked all the plugs, wires, no vac leaks, and no exhaust leaks. It runs smooth, no misses. SOTP is hard to tell since I havent driven a car in 3 weeks. The ONLY thing that is a little different is that my IGN Volts is about 13.1. But it has been reading that for about a year. I am getting the alternator checked tommorow to be sure. The O2 sensors are original and the car has 56k miles. I would hate to buy 2 new sensors if I dont have to. Can someone please help me with this??

 

Are the o2's tight inside the headers?. I just noticed mine were loose after tightning them about two weeks ago. My o2's were reading alow and ver inconsistant.

 

Post a link to one of the data logs.

 

You can monitor PE mode in the Status Bit display (right above the time slider) in Datamaster. Just double-click one of the yellow bit names, and change it to Power Enrichment Mode. At least it will show you if/when the PCM is going into PE.

 

Here is the link to it.
http://www.savefile.com/files/253020
Thanks for the advice about PE mode. I never knew I could change the display in that box. Learn something new everyday!

 

Something sounds off, but please don't rely on your O2's for tuning. You must have a wideband. Narrow band O2's simply are not accurate at anything much different than stoichiometric.

Todd

 

an update, the O2 values are getting worse, as they go from 0 at times all the way to 999. They still oscillate, but its like they do the same thing no matter what Im doing (idling, WOT, driving, etc). I am going to buy 1 new O2 and swap it out, to see if that helps. Ive noticed my pacesetters(1yr old) coating is starting to look not-so-shiny and a little rough. They were smooth and shiny not too long ago. Maybe the coating has damaged the O2 sensors?

 

fixed the prob...actually there were 2. The o2 sensros were on thier way out, and the real culprit was a dirty MAF. My AFGS seemed low, and now I know why. They went from 220ish to over 300 after cleaning. Thanks for everyones help

 

I had the same problem, it's a beautiful thing when you have a clean MAF. Problem solved.