GMC Troubleshooting Questions? Ask a Mechanic for Answers
Did you ever complete the test or whatever on the #1 fuel injector or poppet?
There is one more thing that is most of the time overlooked and that is a wiped or flat cam lobe on that cylinder.
I recently bought a chevy small block cheap that had a wiped cam lobe on the intake side of #7. The previous owner must have tried everything to get rid of a misfire, spark plug, wire, etc but come to find out I bet he never knew if was a wiped cam lobe.
Yes, I installed a new fuel injector. How can I tell if I have a wiped cam lobe?
Measure the cam lobe lifts on both and compare them to the specs or just compare them to the cylinder next to it. You may be able to tell though by just watching how much each rocker arm rises on the side where the pushrod is and compare it to the cylinders on that bank. If it's too fast to see when the engine is idling then remove the fuel pump fuse or relay, so the engine won't start and just look at the lifts while cranking the engine over with the starter.
In order to measure correctly though you would need to use a dial indicator.
Will try and get back with you...I will also check the lash and look for broken spring