Quote:
Originally Posted by shortboxin
Thanks for the reply!
The PCM is from a 2002 Chevy Tahoe with DBC. I don't know specifics as to model number if that's what your asking. It has been modified, but pretty much only to remove anti-theft and rear O2s. I had wondered if the guy that tweaked it may have made a mistake?
Everything stayed stock.
I can double check this, but I'm pretty confident on this.
No CEL on the truck yet, but no codes in the scanner. Sorry, should've mentioned this up front.
I have not done anything more than a quick clean. Thing is that it never feels like it's sticking when I press the gas. Additionally, the truck sounds like it's on the verge of stalling when it's at 550-600RPM.
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Its a little weird that it sounds on the verge of stalling at that RPM with a totally stock engine. Does it ever high idle when its cold? Or does it keep trying to find low idle?
Have you checked your fuel pressure at all? Whats the fuel system setup?
I'd give the TB a more thorough cleaning. Not all I found felt sticking - but they all seemed to benefit from a good cleaning. Both of the 5.3's I have here are DBW so I dont have a DBC throttle body here to look at.
Removing VATs and the rear O2's (disabling secondary O2 bank) really shouldn't cause this issue - even without O2's hooked up it should idle (mine did, just really rough.)
Do you have any exhaust leaks BEFORE the O2 sensors? What is the exhaust setup? Its hard to tell from the video but it does sound like theres quite a bit of exhaust leak. Might just be the video.
What is your intake tract setup? Are there any modifications to the engine? Specifically, cam?
In this video, this is my truck at "cold" idle (air temp was around 80) - around 750-800rpm.
https://www.youtube.com/watch?v=kUoSWj7fvXo
At the beginning of this video, you can hear what hot idle is, fluctuating a bit between 525 and 550. I still need to do some fine tuning to this tune (this is a 6.0 tune thats been adjusted for my displacement and injectors, done by PSI, but I'll be picking up HPTuners and fine tuning it.)
https://www.youtube.com/watch?v=nWyB34SdS9U
Yours sounds like its running rough through the whole RPM range that was in the video you posted... I know you checked for vacuum leaks, but if the cam it stock, it does sound like a vacuum leak. All the ports are plugged off on the TOP of the intake, correct?