Already did a search. Working on '03 expy 5.4., original complaint was no start.
Starter would spin but not engage ring gear. I verified complaint and starter would kick in and out, kind of half engaging ring gear. Engine did half a** turn over and backfired on drivers side. puff of smoke cam out around exh. man. installed new starter and engine will not idle. Can hold rpms @ 2k and above with throttle and runs smooth but will not idle. No check engine light yet. ran fine before starter went. Was thinking IAC valve but could it be possible that the backfire damaged the egr valve and is stuck wide open allowing a large vacuum leak not allowing idle? Had to get to work so I did not have any time to t-shoot further. Will finish t-shooting tomorrow. Just wondering if anyone had something similar happen. Thanks!

 

possibly a timing issue??

 

I'd think you dumped a lot of fuel into the cylinders trying to start it, thus the backfire. There's prolly some carbon built up somewhere.....

 

Can these egr valves be checked with a vacuum pump. ( see if holds vacuum) I know some vac operated valves cannot be checked the traditional way ( ex. gm iron duke) thanks

 

Well it was a quick fix. When the engine backfired, it blew the pcv hose off the back of the tb. Checked for any cracks, holes. Reinstalled. Idles just fine now.