I have a 1982 el camino. It was my grandfather and he bought it from another guy that had swap the engine to an automatic 91 corvette 350 tune port injection and 91 corvette transmission. I am trying to fix it up but the engine keeps turning off on me once i turn it on or when im at a stop light or when i put it in reverse. It also stalls out on me on the road when im driving it at random. Sometimes it works fine but sometimes it doesnt. I changed all the spark plugs and wires, and all new injectors, and checked the gas tank for dirt, I also changed the fuel filter and it had tons of old dirt that looked rusty and changed the oil and oil filter. Can anyone help me figure out what is wrong?