ok this is an update to a previous post. i have a 1991 S10 blazer4.3L. had some idling issues and power loss issues. initially thought is was bad fuel or fuel filter and pump. not it. then injectors...not it. replaced spark plugs, wiresand distributor cap/button...not it...then we decided it was the timing. well doing that it still ran like crap and still had power loss. so we decided to spray carb cleaner on and around the engine. well sure enough there was an intake manifold gasket leak. so after lots of beer and time, we were able to replace the gaskets and seal it back up. once we started it up again we noticed that it idled alot better but there was still a loss of power and now the carb was smoking a bit and caught fire a few times. not sure what is wrong now. thinking mebbe it is a sensor or chip problem or computer issue mebbe even a valve is off somewhere. anyone have any ideas before i strap some det cord and 35 lbs of C4 to the truck and "fix" it for good.

PS the trying to do the timing on this bad boy is hard as hell.

Thx for any input. Jay

 

Well, it isn't necessary to create a new post on this, but whatever...

Have you done a compression check on the motor? If so, what were the results? All cylinders should be within +/- 10% of each other in a healthy engine. If you find that one or more cylinders fall outside of this tolerance, squirt some oil into the cylinder and retest. If it brings it back up, you have ring issues. If it doesn't, you could have a valve or cam problem.

I'd start there and see what you come up with.

It is possible that you have a worn cam as well. To check that, you'd need to remove the valve cover and check the valve lift... Really needs to be done with a very light spring in place of the valve spring to keep the lifter from compressing, but that is quite involving...