Radio plays just fine with engine off, crank it up and radio cuts in and out rapidly. Turn engine off, plays fine again, Radio used to work just fine, but after I got back from the repair shop for an electrical ignition problem, this problem showed up. Any ideas?

 

Sounds like electrical interference. Is the ground strap from the back of the engine to the firewall intact?

 

I will have to check and see.

 

Yes grounding strap from engine to firewall is in place.

 

You need to check your grounds. Start with the battery cables (2 ground, 2 power, plus one FROM the alternator). Don't just look at them. See my sig, #1.

Since it happened while it was in the repair shop, the problem is almost certainly under the hood, unless the were working on your dash. If they were inside, then check the ground to the radio first.

 

Now that we've eliminated that variable, it's likely something got screwed up when doing the ignition work. I don't have much to add specifically, but what sort of work did they do? Something with the ignition circuits under the dash or something with the ignition system under the hood? Also, does the radio problem change at all based on engine speed?