1995 Chevy Camaro 95 Z 28 Camaro

I HAVE HAD THE ENGINE REBUILED AND THE ELECTRONIC IGINITION KEEPS GOING BAD. PUT A NEW ONE IN AND IT MAY LAST UP TO 8 WEEKS GIVE OR TAKE, I CAN ALWAYS TELL WHEN IT IS GOING TO GO BAD. IT STARTS TO BACKFIRE AND RUNS POORLY. I HAD TO REPLACE THIS ABOUT 10 TIMES AND IT IS COSTLY. I RECENTLY TOOK IT TO GET REPAIRED AGAIN AND THEY DID NOT CHANGE IT OUT. SAID IT WAS A GROUND WIRE AND I NEEDED TO CHANGE THROTTLE POSITION SENSOR, IDLE AIR CONTROL SENSOR AND POSSIBLE THE MASS OBDI SENSOR. THEY HOOKED THE GROUND WIRE UP AND IT CRUNK UP BUT RUNS POORLY. WHEN YOU FIRST CRANK IT UP, IT DOES OK BUT WHEN IT WARMS UP IT STARTS TO SHAKE A LITTLE AND JUST DOES NOT HAVE THE POWER IT SHOULD. PLEASE ADVISE.