Engine Shakes after Warming Up

What would cause my engine to shake in my truck after it reaches operating temperature. I brought it to my mechanic, and he scanned the computer, and it said the EGR valve was bad. So I had them replace that along with the solenoid. I changed the plugs and wires 6 months ago, so those should be find. It runs and drives great when you are moving, but while idling it shakes the whole truck, and surges foward at times at red lights. It is a 91 s10 4.3 auto with around 110,000. Any Ideas??

Justin

ok here u go. http://www.autozone.com/servlet/UiBroker this is a small description of what the problem may be. check all that apply to u. also, check motor mounts (i know that it would shake all the time, but its worth a try) trany mount. also, a clyinder may NOT be firing or the injector to that cylinder may NOT be getting fuel. try all of these and get back to me.

What would cause my engine to shake in my truck after it reaches operating temperature. I brought it to my mechanic, and he scanned the computer, and it said the EGR valve was bad. So I had them replace that along with the solenoid. I changed the plugs and wires 6 months ago, so those should be find. It runs and drives great when you are moving, but while idling it shakes the whole truck, and surges foward at times at red lights. It is a 91 s10 4.3 auto with around 110,000. Any Ideas??

Justin

use vacuum gauge and check for leaks. vacuum should be greater than 19in at idle. pcv hoses highly suspect