This is a long story so bare with me. I purchased two trucks last year a 1978 K-20 Silverado dieing of rust but with a strong drive train and a 1977 C-10 Scottsdale with a nice body and a dead engine. The K-20 ran fine nothing wrong with it at all never had any trouble. I swapped the engine from the K-20 into the C-10 and replaced the stock carb with an edelbrock from the dead engine that was originally in the C-10. The previous owner of the C-10 said it was a new carb...and it did look new.
After the engine swap the C-10 never ran right. I took it on a long hellish camping trip where it performed beautifully on the freeway but as soon as I pulled off the freeway and stopped at a stop light or stop sign the trucks idle would become very rough and it would die. Afterwards it was very very hard to get it started again (but it would always start up again thank God).
This winter I was driving it around a little bit and didn't encounter the problem again until the temperature got a little higher (above freezing). Now it's doing it again. I can start the truck in the morning and its fine but as soon as I take it for a short 10-15 minute trip and its warmed up it will start to idle really when I come to a stop.
I couldn't find anything wrong so I took it to a mechanic and he said there was a vacuum leak. He fixed it for free and I was on my way. But yesterday the problem was back again. I was idling at a stop light when I could feel the engine starting to die on me. I had to hold down the break and give it gas to keep it running.
When I got to work I put it into park and turned it off and then started it back up again after about 10 seconds and the idle was really bad it was barely running I let it idle like that for about 10 seconds and then it stalled.
I really need this problem resolved because this is my daily driver and it's barely getting me to where I need to go. Not to mention my wife refuses to drive it because she's scared to get stranded somewhere. So any help is greatly appreciated.