Hi all,
I have In 83 k20 with a 350. At idle I have 4 cylinders running strong with the other 4 being intermittent. I have checked spark which is all good. I have checked compression and valve timing. All good. I have but in a brand new distributor all new plugs, new cap and rotor. I dont know what else to look for. Please help me.

P. S. I have also checked plug wires and they are perfect.

 

Please help me with this.

 

Is this the original engine or has it been changed to a newer one? Just wondering if it is a newer engine with AFM.

 

This is the original engine.

 

Id say replace the pickup coil in the distributor, make sure the base of the coil is not grounded

 

Could very well be the pickup coil but it is a new distributor as he said. I would also see if you have a vacuum leak at the intake on the side with the 4 weak cylinders. Did all this happen at once or right after some work done to it? When you say compression is good, what were the readings? Plus you may have an intake problem not allowing equal amounts of fuel to the effected cylinders or even a bad carb that is causing the problems. Did you check the carb adjustment for equal adjustment?