1992 Chevy silverado firing on 6 cylinders instead of 8?

Answer 1

You need to diagnose the problem, verify which cylinders are not running, ignore the look of the spark plugs and wires on those cylinders, replace them. check the distributor cap and rotor for any damage even fine hairline cracks. replace as necessary. all that is ignition stuff. If it turns out that the ignition system is not the failure then move to mechanical. Remove the valve covers and verify that all rockers are traveling A equal distance. especially the ones for the cyls. that are not running. Do this by using the starter to turn the engine (BE SURE TO DISCONNECT THE IGNITION SYSTEM FEED SO THE MOTOR WILL NOT START) Watch the rockers closely to determine the amount of travel if it is less for the downed cyls. then its a bad cam or possibly A lifter or A rocker is lose or A valve is broken. If they all have the same travel, Use A compression tester, This can be purchased from A parts store for about 35 to 40 dollars, Without starting the motor remove all spark plugs and one at A time screw the tester in each plug hole, crank the motor with the starter for about 5 to 10 seconds wright the compression on paper, The engine should be within 20% across all cylinders. Example: 155lb,160lb,155lb,140lb,165lb,155lb,155lb,45lb,,,,,, This motor has damage to #8 cylinder, The rest are in acceptable range. ,,,,,,,,,,,,,,,,,, The pounds of compression are not nearly as important as the range., Generally anything over 90lbs will run.,,,,,,,,,,,,,,,,,,,,, If you find Acompression problem and do not know what to do, I suggest you take your vehicle to A repair shop.