my engine is kicking out a p0303. which is a #3 cylinder misfire. i tried to change the coil pack, spark plug wires, and spack plugs. nothing changed. i got a compression test and there was no compression in that cylinder. any suggestions?

 

Thats not good, when did this happen, how were you driving the car?

 

i was going from 3 gear to 4 at about 4500 rpm. then all of a sudden the engine light came on and blinking. so now when i am at 26 mph the engine light in on, but when i go over 26mph it blinks.

 

Its definitly a misfire, My buddy had the same problem with his Denali, he repalced one of the injectors and problem solved, no more misfire.

Your still getting spark just no compression. Maybe your compression ring took a dump.

 

Little or no compression usualy means a valve issue. Could also mean a head gasket problm

Pull the valve cover and start from there. Make sure that the valve train for that cyl is working correctly. No need to GUESS your self to death. Remove the plug. Bump the engine over until that cyl is on the compression stroke (both valves shut). Use compressed air and pressurize the cyl thru the spark plug hole. If you have a compression issue, the air will escape out of the problem area. Listen in the intake throttle body(throttle blade open) for a intake valve issue, listen in the exhaust pipe for a exhaust valve issue and if you have a piston issue, you will be able to hear the air from the open valve cover. Where ever you hear the air, that will be the issue.

BC

 

 

What Bill said. I would eyeball those valve springs real close too.