Engine stumbles like it is starving for fuel or air?

Tiny
B. PLAIR
  • MEMBER
  • 1997 CHEVROLET TAHOE
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 268,000 MILES
My truck runs great until after about ten miles of driving then all of a sudden it can't get out of its own way. I can shut it off and immediately start it back up then it runs like it should but only for a limited amount of time. I've replaced and upgraded the fuel injection, new GM pump, fuel filter, coolant temperature sensor, mass air flow sensor, new plugs and wires, cleaned the throttle body and replaced the gaskets on both the throttle body and upper intake. I'm completely lost, please help.
Thursday, August 4th, 2022 AT 11:18 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,513 POSTS
Are there any codes? I would run them even if the check engine light is not on. Here is a guide to help. You can get a code scanner from Amazon for about $20.00.

Here is a guide/video to show you how:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Here is a scanner link:

https://amzn.to/3Qi1SS6

You could have a PCM going out which will cause this problem and is common with that many miles, and when this part goes out it will not have a trouble code FYI.
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Friday, August 5th, 2022 AT 5:11 PM
Tiny
B. PLAIR
  • MEMBER
  • 2 POSTS
The only code I'm getting now is a misfire on #6 but that only pops up after the truck starts running funny. Thanks for the link but I already have a scanner. When I look at live data, the MAF reading is always in the red along with the TPS when I accelerate. How do I confirm that it is or isn't the PCM?
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Friday, August 5th, 2022 AT 11:18 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,513 POSTS
The only way yot see if the PCM is bad is to send it out and have it tested.
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Saturday, August 6th, 2022 AT 7:42 PM

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