I've had a '99 Automatic 4Runner with 85k miles for about 6 months. The truck runs well with no noticeable problems but for a sporadic (once or twice a week) tendency to stall usually after coming to a stop after longer periods of driving (usually highway). It always starts back up immediately. There are times it will sputter a little when waiting at a light as well, without actually cutting out. I've had a couple mechanics including the local dealer check it out, they've done a few things, including replacing the throttle position sensor but to no avail. I get the sense I could spend dough all over replacing sensors without necessarily fixing the problem, so any help would be appreciated. Thanks.

Might be your EGR valve is clogged. Clean out the EGR with a coat hanger and carb cleaner or replace.

One thing you can try that won't cost much is cleaning your throttle body.

http://www.4x4wire.com/toyota/maintenance/30_V6/throttle_body/

Has your "Check Engine" light come on?

If you want to try something - try replacing the ECT sensor.

http://i16.photobucket.com/albums/b8/rogersb/5VZ-FEECT.jpg

Thanks for that. The problem has been around for about 6 monhts with no check engine light until a couple weeks ago. It was on for a day and went off. Took it in and it read throttle position sensor, so replaced that and the light is fine now, but the problem still persists.

ECT sensor