UnStick a Stuck valve

[rushtk]

I have a 99 Tahoe 5.7 and have not been able to do a compression check but I am told cylinder 3 is dead. Happened after we put new plugs, wires, coil, and distributor on it. Does anyone know of a way to unstick a valve without taking it apart? This is the houses only vehicle at this time and down time will not be happy time! Thank you for your thoughts,

 

[Jimmyy]

I would start with pulling the valve cover off to get a better idea what's going on.

 

[Fless]

Define dead. What details of the diagnosis did you get?

 

[exp500]

AC Delco/Delphi/GM or United DCR820x cap/rotor only! This could be your problem.
Stuck valve, Change oil immediately. Add 1/2 qt ATF to oil. Remove valve cover and inspect Rockers, pushrods, lifter height compared to other cylinders (need to rotate engine) I usually use the Alternator rather than crankshaft bolt to turn. If valve is stuck, likely that pushrod is bent.
I'm thinking/hoping that it is electrical because of recent work. These trucks have a serious hate for haphazard ignition work or cheap parts. A spark test at coil and distributor would help define also.

 

[JackFox]

I would say a stuck valve means head is coming off. Your nexhaust valves are probably a bit burned up anyway, if you are anywhere near 200K miles. It would be worth it just to replace the exhaust valves and lap them in. New seats if needed, but I usually just see the valves a little burnt (meaning pitted with carbon deposits and overall black look instead of shiny). But pull off that valve cover and take a look! also, you can removed the rocker and tap directly on the valve stem. You see a valve that is lower than the neighbor, with the rockers off? There's your stuck valve! Tapping it a few times can get it un-jammed. Cleaning things because of sticking valves can work if it is indeed build-up. But I always recommend Top end rebuild if you got the cash