Hi,
I've been having some trouble with my '80 Pickup. It starts, idles and runs fine until it warms up. After about 10 or 15 minutes with the engine warmed up it begins to quit. That is, the engine refuses to idle and the rpm drops to zero. The same thing happens when I shut the engine off then restart shortly thereafter. It seems to me like a vacuum or vapor lock problem. The previous owner replaced the stock mechanical fuel pump with an electric one that seems to pump a little too aggressively, could this be the source of the problem? He also replaced the carb with an oem rebuild. I tested the resistance of the thermo sensor in the caltalytic converter,when trying to diagnose the problem and it seems to be bad. Should I replace the catalytic converter and go back to the mechanical fuel pump? What else could casue this issue? Thanks.

I'm not sure what's causing your problem, but if you say that the electric fuel pump is basically flooding your engine all the time, that would probably be a good place to start.

I tookl a closer look at the fuel pump and ran some tests. It seems to be in good working order. I was just a little leery of it since it is quite loud, but fuel level in the carb is just right. It turns out the noise is only vibration against the side of the engine compartment, remounting fixes this. I guess for now I'll replace the cat. coverter and thermo sensor (which are most definitely shot), then later I'll move onto emissions and vaccum issues. I'm starting to think the idiling problem may be the egr valve. If this gets stuck open and dumps too much exhaust gas into the engine it would kill it at low idle, right?