Hard to diagnosis problem

[debbie]

I have a 98 Tahoe LT with a 5.7 liter engine. It has 266,000 miles and I am the original owner. When going uphill at 60 mph or above, the engine stumbles. This never happens during city driving. I can take my foot off the gas for a second or two and the stumbling stops. At times I will get a random misfire code when this happens. I have new plugs, wires, cap, rotor, air filter and fuel filter was replaced 20,000 miles ago.

Any ideas would be appreciated.

Debbie from Memphis

 

[SARNCAN]

I have a 98 Tahoe LT with a 5.7 liter engine. It has 266,000 miles and I am the original owner. When going uphill at 60 mph or above, the engine stumbles. This never happens during city driving. I can take my foot off the gas for a second or two and the stumbling stops. At times I will get a random misfire code when this happens. I have new plugs, wires, cap, rotor, air filter and fuel filter was replaced 20,000 miles ago.



Any ideas would be appreciated.



Debbie from Memphis

Try cleaning throttle body