Mechanics

5.3 VORTEC LOSES POWER AT HIGH RPM'S

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.
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Zen57
December 10, 2011.



Check/Test the MAP and TPS sensor

Rasmataz
Dec 10, 2011.
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.

Tiny
Zen57
Dec 10, 2011.
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)

Tiny
Zen57
Dec 11, 2011.
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.

Tiny
Gearjonny
Dec 12, 2011.