'90 626 lx starts then stalls

Hello everybody-

My name is Johnny and this is my first post.   I'm more of an old car guy, but I'm trying to save my '90 626, you guys are my last hope!

626 lx 2.2 l4, automatic.   128k never a problem until two weeks ago.   Left lights on while at work, started up on its own, then stalls after about 6 seconds.  You can set your watch to this 6 seconds, either on the accelerator or trying to let it idle, makes no difference.

Here's what I've done: 

Battery holds charge (even tried new battery out of another car just in case), alternator charges, tested this with voltmeter, all belts replaced 4 months ago, still there and OK.   New spark plug wires, spark plugs clean and gapped correctly, distributor cap is fine.  Replaced fuel pump (old one blew fine though).   Took it to a mechanic, he and his son spent 4 hours and couldn't find anything.   Mass air meter didn't ohm exactly right, so I replaced that.  The mechanic said he got no error codes.   He was able to keep it idling by throwing immediately into D then back to P, long enough to reach operating temperature.   Then he adjusted the idle screw and I could drive it home, with the check engine light on and not running correctly, smelled like it was running rich.

At this point I am at a total loss.   Car has always ran great, very smooth, never stranded me before, didn't gradually run badly.   This and the problem starting when the lights were left on leads me to think it's somewhere electrical.

I would GREATLY appreciate any help you all could offer out there.

Thanks-   Johnny

Hi there I remember you posting this on the 626 forum, but as we know that forum went bye-bye. 2 things I would check: #1 check your air intake boot, they are notorious for developing cracks, even the tinyest hairline crack is enough to make it run like crap. You can find them on e-bay for around $50, but if your tight on money, duct tape will work so long as its airtight. #2 is your ignition module, also notorious for failing. It is this half-circle shaped thing under the distributor cap, but they are quite pricey, I was able to find one for $99, but they average around $170.