82 Trans Am, LG4, Q jet

After driving for around 10-15 minutes from warm up, my radio starts to turn on and off. Soon after, my check engine light flashes 3 times (I think) with it. The motor was running fine.

I just took out all of my smog pump equipment, and taped up a connection from the computer a few days ago, and did not have a problem in the meantime. What's going on?

 

first check for trouble codes stored in the computer.

after that, once you find nothing there, follow the grounds from the radio back to where it grounds at. Clean it off, and any other grounds you have around the area... sounds like a ground loop.

 

After driving it home, the motor warmed up to just below 160, and radio turns on and off, check engine light turns on and off, then I notice the tach says 1600 rpm, when I can hear it idling. With my blinker on, the tach goes up a few hundred rpm insynic with the blinker. When I turned the heater on, the fan was not working to well, and the tach went up to 4 grand, while it was really around 1500. I park at a garage and when I try to start it 10 minutes later, the battery is dead.

The mechanic said it's most likely the alternator.

 

I had a similiar problem. My radio would randomly go on and off, and so would the SES light. Turned out one of my battery cables came loose and would connect and disconnect.

 

The problem was the wires on the back of the alternator were corroded. After some cleaning, it works well.