I'm trying to help a friend of mine diagnose a problem with his 84 Camaro. He dropped in a Caprice 305 with a regular Rochester 4BBL (no electronic solenoids) carburetor a while back, and the car recently started running poorly.

He says the car lacks power under acceleration, and that the idle is erratic when he stops at a light. The engine idle will drop, then pick up, then drop, then pick up, and so on. It's kind of rough, too. Fuel delivery, including the filter, checks out good. He also says the timing is ok. Any ideas as to why the car would suddenly start running like this, after running well for 2 years? Where should we start troubleshooting?

 

The ignition system. Cap and rotor, then plug wires.

 

Then choke and vacuum.