When my TBI RS is at idle #8 cylinder is not running. Any wire i unplug changes the motor except #8, but #8 plug is getting good fire. Also at idle the lights get dimmer when it misses. This is getting real anoying, i have changed or checked everyting ignition related. Can a roller cam wear a lobe I hope its not internal IT has even compression #s
There could be something simple that i am overlooking.
Its been this way since i wrecked the car, it sat up for a couple of months while i fixed it

 

Have you replaced the spark plug? I know you said it had spark on #8, just didn't know whether you meant at the end of #8 wire or at the end of the #8 spark plug. I would go through and change all the plugs first then go from there. Make sure that #8 wire isn't melted through and grounding out on something also.

 

yes the plug is good