chris2001chevy

I am new to this site. This is my first truck I always owned imports but I needed a truck. My name is Christopher. My truck is a 2001 Silverado 1500 series with a 4.3L in it. The problem that I am having is this. I kept on getting a crankshaft sensor circuit A code and I changed the sensor. After replacing 3 of them because of that code coming back I decided to take it to a garage. They checked it out and they put a new one in and did the timing chain and componets with the crank sensor pig tail. Truck ran fine for a week then that is when it all happened. The tach would go nuts at 2000 or more. It would bounce up and down and the truck would feel like it is skipping when it did that. Problem got worse so I took it to the shop again. This time so far I have had the crankshaft sensor again replaced also with the camshaft sensor, distributor gear, engine computer that was reflashed to truck ( The one I got came out of a 2000 chevy blazer with a 4.3) and the mechanic even went and bought some piece of the engine harness and we are still having this problem. Any ideas. Is there by some some chance you can get a bad computer. I want my truck back. Thanks