Fuel trims were reset after the O2's installed. Now they are where they need to be. Finally got the weird running issue done...to find the time to yank my tranny and install the goodies I have waiting...Trailblazer I-6 TC, HD2 shift kit, Trucool 40k and the new filter. Then the performance mods are complete.

 

I believe someone said somthing about a bad 02 sensor at some point... Haha. Glad you got it figured out.

Couple days after i was at your place i got sent to another location and didnt get back till right before i had to leave.

 

LOL yes I believe someone with a user name like yours might have lead on to the discovery of the problem.

Hey that is the military for ya. Thanks for stopping by. I appreciate you taking a look at it.

With the Wheatley tune...OMG does the truck run good. Especially after the new o2's and a fuel trim reset.

 

Don't mean to thread jack, I see that you got your problem fixed. But I am having a very similiar issue with my s10 that has a 2003 5.3.

I put 2 new o2 sensors in it that should fit the 2003 silverado 5.3, because the ones that came with the motor were universal junk and they were both setting codes p0134 & p0154.

After i replaced them with bosch parts, it ran like crap, wouldnt idle, was barely drivable, it only ran good at WOT. Only code was P0171, lean condition on passenger side.

I put the universal O2's back in and boom, runs fine but with codes. I have LT headers, on the passenger side I may have a small exhaust leak, I can hear it under light acceleration. Would this throw off the o2 sensors? I have ruled out almost all other possible causes of it running like crap, the fuel pump is new, new intake manifold (no leaks), clean MAF, getting spark on all 8. So i know the issue is with the 02 sensors. ANY IDEAS?!

 

My problem is solved so you can jack the thread. Information is Power!
1. IMO Brand new Denso (AC Delco)O2's. I got mine from Rock Auto (paid $105 for the set). I haven't heard anything good about universal o2's working good on headers applications. Doesn't mean they wouldn't, I just havent heard anything good.
2. Definitely fix your exhaust leak.
3. Make sure you reset your fuel trims. My LTFT's were way out of whack due to them trying to settle down the STFT's with Jacked up O2's.

 

I picked up Denso O2 sensors from RockAuto for $35 each...they have a bunch of different options in their listing, and a few different Denso options. The price may have gone up though, it was less than a year ago when a got them, but it was a while ago...

 

I think my problem is coming back...

I will run a log to find out this morning...

Edit: LTFT were not high, they were running negative?

 

Means they are pulling fuel from being rich.