I have a 2000 ZR2, 5 speed, 177k miles. Lately it's been running rough. It will idle fine and run fine when I'm giving it throttle. When I get up to highway speed and let off the accelerator it starts bucking and act like it's missing. As soon as I press the gas pedal it smooths right out. I recently replaced the spark plugs, plug wires, cap and rotor, fuel filter, and throttle position sensor. The other thing is that after the truck runs for awhile, the problem gets less severe. Anyone else experience this?

 

Possibly bad gas,put some dry gas in and see if it helps it's never a bad thing to do every few months anyway.

 

*Moved to: 2nd GenS-series (1995-2005) Tech*

 

Any codes yet or pending?