I am in the process of purchasing another Z71 (99' with 200,000 miles). The truck runs and looks great except for one thing. At low RPM's the truck begins to "bogg down". By that I mean that it starts to kind of vibrate or bounce slightly. The seller is positive that it's a coil (which he has already replaced) that isn't firing correctly. It doesnt feel like it's the transmission but we are still taking it to a mechanic tomorrow to see if we can get a better analysis.

I just wanted to throw this out there and see if anyone else has had a familiar experience.

Thanks

 

could be fuel pressure,distributor gear,old style spider injector assy,when was the last tune up?