5.3 vortec loses power at high RPM's

Tiny
ZEN57
  • MEMBER
  • 1999 CHEVROLET SILVERADO
  • 130,000 MILES
Replaced fuel pump recently along with filter, pressure regulator and TPS. Truck seems to idle fine runs good until I get on it, then it bogs down and won't accelerate. Could drive forever with 1/3 pedal but try to pass someone and forget it. It sounds almost as if it is choking itself.
Saturday, December 10th, 2011 AT 1:11 AM

4 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check/Test the MAP and TPS sensor
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Saturday, December 10th, 2011 AT 1:30 AM
Tiny
ZEN57
  • MEMBER
  • 2 POSTS
The tps is new, still have the old one. It runs the same with either the old or the new tps on it. It is exhibiting some of the things a MAF sensor could be doing such as a tremendous loss of power when you step on it. It runs better with the MAF disconnected. I unplugged it and was able to get up to 65-70 on the highway trying to get home with it. The MAF sensor looks fine, it is clean and all connections look fine. I am going to test it and see what I come up with there.
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Saturday, December 10th, 2011 AT 3:04 PM
Tiny
ZEN57
  • MEMBER
  • 2 POSTS
Tried a new MAF sensor. That didn't cure it either. That doesn't leave a lot. New TPS, new MAF, new fuel regulator and new fuel filter. What else could it be? Knock sensor, O2 sensor, clogged cat?Also, not that it should matter but there are also new plugs and wires. I am at my wits and my wallets end. It runs better but the biggest improvement seemed to come after the plugs and wires.
I also run sea foam through it regularly(monthly)
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Sunday, December 11th, 2011 AT 5:21 PM
Tiny
GEARJONNY
  • MEMBER
  • 1 POST
Remove an upstream 02 sensor and test drive it. If a cat is clogged, the truck will run great with an open hole to flow exhasut through. (Keep in mind you will have to clear an oxygen sensor code after driving with it out.
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Monday, December 12th, 2011 AT 3:44 PM

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