I think i have narrowed it down to my AIR system. I thought originally that it was my EFE but have have disconnected that and it is still there. The clack is on the Passenger side when it is colder outside and the engine is not fully warm. Sounds similar to an exhaust leak but stops when the engine is warm (after about 2 miles). Don't hear anything at idle.

I was wondering which AIR part it could be:

1. check valve on passenger manifold AIR Tubes? (Air Tubes are new 2 years ago. Clack was there before changing tubes)
2. Diverter valve
3. Silencer
4. AIR pump itself.

Anyone have any experience with this type of noise or which part could make that noise. All parts listed are original 1983 OEM.

thanks,
phil

 

turned out to be the mechanical fuel pump.