Hello all new to the forum, I have a 360 long 3 cylinder diesel. I recently replaced the starter, now It doesn't run right. I really notice it above 1500 rpms it spit, sputters and backfires really bad. It actually gets better after it has warmed up. During the installation of the starter I had to remove a plug from injection pump right above the starter. My question is before I send it to the shop, does anyone know what the plug is for, possibly the fuel pressure regulator. None of my manuals even mention this plug.Thanks