I have a,,92 GMC c2500 with a 5.7 .I haven't had it very long but it developed a miss so I decided to give it a tune up and install a new distributor.Once installed the engine starts and idles and accelerates in park but in gear under a load cuts out starting at about 1500 rpm and up. Assuming this is due to timing advancement...engine does when I unplug timing wire to time it properly or it does not start with wire unplugged either....how can I solve this timing isdue

 

Welcome to the forum. First i would make sure that the distributor is installed correctly and not off by one tooth.