My car has a history of the occasional stalling problem, where it starts right back up again. But in the last month or so, it's been different. Three times so far, it would stall and then not start for at least a minute. Then once it starts, it's perfectly fine again. Normally the engine runs with hardly a miss, no smoke, and decent power. Idle is 700/550.

This has me a little spooked now, as it did it again today while pulling into my driveway. It usually happens while slowing down or stopping, but one time it acted the same while trying to start it hot in a parking lot. Not knowing better, I would describe the symptom as very temporary vapor lock.

This is the worst problem to diagnose because it's intermittent. Has anyone had this problem and figured out the cause?

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1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma

The idle control valve may sticking shut. When it stalls and won't restart smack the valve with a screwdriver handle and retry.
Mike

Do a search on Fuel Pump Relay. You can jumper the terminals when the car won't start in order to eliminate it as the culprit.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

The FPR was the culprit a few months ago, when the car would not restart at all. I redid a cold solder joint, and that fixed it. However I am not ruling anything out. I have my emergency wire in the glovebox.

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1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma

My FPR was resoldered once and still caused the behavior similar to yours. Each time it stalled or failed to start I inserted my paper clip and it started right up. So I ordered a new FPR, and it never happened again. It has been a year with no problems, and I drive it daily. It might not be a bad idea to consider a spare FPR anyway...

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Sure enough, the engine failed to restart, I took out the FPR, shook it and plugged it back in, and it starts. This was repeatable several times. All the solder connections still look OK. So like a caveman, I whacked it against something hard and that fixed it, for now. A new one is on the way.

__________________
1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma