steve porch
Newbie
I have a 99 Chevy z71 and the truck idles fine it runs and shifts fine until about 35mph or 3rd gear. I've noticed it will drive around 2500 rpm range in 3rd gear I have to give it more gas to get it to shift into 4th. When giving it more gas the truck shakes and shudders until I either let off the gas or give it a lot of gas then it will kick itself out of the shudder and shaking. Once it's in 4th and I'm driving with a steady hold on gas pedal about 2000 rpm it will get rough for a few seconds then drive normal. Then back to rough and back to normal constantly. There is only a slight change in rpm when it does this. Do I have an ignition or tranny problem? There is a slight grinding noise also