mystery!

Hi All
New to the forums, and have found them to be a great help so far.
I've got a bit of a problem, that seems to have disappeared for now.

Approximately 2 weeks ago, I came out of work- tried to start up my 1999 rodeo (3.2) (60k mi) it would start and them die out. Wouldn't idle on its own above 4 or 500. I drove to my parent's house nearby, putting in N at stoplights and manually revving engine to keep it going.
After sitting for a few hours I went to start it up, it was idleing at about 2500.

I took it to my usual mechanic, he could find nothing wrong. He kept it a day test driving it every few hours to try and duplicate the issue. He couldn't make it happen.

As of that trip, the problem hasn't reoccurred. Any suggestions as to what happened?

it could of been water in the gas (add a bottle of that stuff that is suppose to dry up water to the gas tank).

or it could be the intake manifold gasket letting go (very very common). The broken part of the gasket could of moved a bit to seal up the problem for now, but it could come back. Almost all 98-00 isuzu's have had intake manifold gasket problems (I had mine changed on my 2000 at 54k).

Yep, my bets would be a split IMG, or maybe a sticky idle air control valve (top of the throttle body). 1998 and 1999's have the IAC, 2000+ do not thanks to the TBW system.
G/luck
Joel