Chevrolet Repair: 1995 Chev Blazer (S10) 4X4, chev blazer, blazer s10

Question
I have a Chev Blazer that has electrical noise when the engine is running, I also believe the idle is rougher than it should be.

I have changed the plugs, wires, rotor, cap and alternator.

I believe the most likely cause is the ign module or the ign coil but do not have any way to test. Can you suggest a test that would uncover which component is the problem? Or is there another component which could be the problem.

I am not sure if an earlier message was sent, if so please delete this message.

Answer
Hi John,
If you are hearing that noise over the radio, I think you have a bad antenna connection to the radio.
Older radios had a port where you could actually tune the antenna for best reception, but I don't think they do any more. But a bad connection will cause the radio to pick up signals from the car, that it otherwise wouldn't.

Van