Air pump questions

[goldenc4]

My 84 C4 has been running great since I got it in August. Now just this week it started to run really rough. Sputters and dies on acceleration. My first thought was bad gas. Put a can of Sea Foam in the gas tank and drove it about a half a mile last night. Opened the the hood and noticed the exhaust manifolds were cherry red. When I removed the air filter cover I also noticed that where the tube comes in from the air pump it is really making a loud chuffing noise. I can hold my fingers over the fitting inside the cover and the air is really hot and is pulsating. Is this normal or does this have something to do with the rough running?
Thanks ahead of time,
Jim

 

[G Winter]

My guess is either a problem with valve/ignition timing, a lean condition, or an exhaust restriction. Such as a catalytic converter. With what you describe, I would lean towards restricted exhaust.

Welcome to the site.

Glenn