Shuts off instantly when put into gear what could be the issue, possibly a vacuum issue?

It started on the freeway, accelerated and my rpms went halfway then all the way over, sputtered and then drove fine. Stopped at 3 lights no problems, the pulled into a driveway and it died. It starts just fine, idle was a little low at first, so I cleaned the throttle and adjacent parts, TCM, etc. Idle went up. Checked for leaks air etc, None that I can feel or hear. I'm at my wits end on trying to figure this out. Turns over great, idles great, then when I shift it into gear it shuts off! Does fine in neutral, tried it in reverse, e brake on, foot brake off, put it into reverse it jerks and then dies. Help me please I've practically rebuilt this engine and I'm going to have a bonfire if I can't get it fixed. Thank you