My 400E has an odd problem. After the car sits unused for 3 days it will run fine for about 15 minutes. After that time span it sputters at idle and idles at about 400 to 500 RPM, plus you can hear the engine missing at idle. Even when revving the engine it will still miss a little. This problem will persist for about 10 minutes after the onset, or until I stop the car. After either 10 minutes or a restart, the car runs fine, idles fine, and doesn’t miss. After this session the car will continue to run fine as long as I use it daily. But when I let it sit unused for 3 days the problem recurs. What is odd is that the problem doesn't recur after 1 or 2 days of non use, but only after 3 or more days of non use. The car stays in the garage when not in use. It has had this problem for about a year now. In this time the problem is no worse than originally, but no different.

Any suggestions?

Thanks in advance!

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...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

Welcome to the club (although you have a V8?):

A good, tough problem- 300e occassional stall after warm-up

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89 300te 222,222
92 300e 190,000

Tracy - shot in the dark - see what tech had to say in this thread:

400E running poorly

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'91 300-SEL

Another shot in the dark. Mine would behave the same way yours did...ran better in cooler weather, but acted funny during hotter months. Seemed to be onery if I let it sit for a weekend.

My indie found a vacuum leak and changed the plugs and the problem went away.

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Thanks all for the comments and references!

r_p_ryan did you get the problem on your car resolved?

G-Benz Mine doesn’t seem temp or weather related at all. Had the same problem in 30 degree temp as it does in 90 degree temp. Rain or sun doesn’t mattter either.

From the literature that was provided the following are good suspects. Has anyone else gone through these and found a solution?

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Just recently in a post I received from a UK forum someone pointed me towards the charcoal canister that forms part of the EVAP system which was a completely new area to me. Reading up about this has lead me to look at the switchover valve and purge valve in the system – the interesting thing about them being that they only come into play when the engine warms up, intermittently cause air (fuel vapour) to be added at the intake manifold, and they are controlled by a vacuum (that I presume could dissipate over time – e.g. 2+ days!).

Not sure if I’m putting 2 + 2 together and getting 5, but on reading “trants4md”’s post to you I did start to get excited – not that I’ve a warm-up regulator either, but could I/we be suffering from a minor vacuum leak internal to one of the valves?

Going to have a good look tonight then the car will be left unused for 4 days over Easter. Will keep you posted if I find anything….


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Hi, I have a 300E and had experienced the same symptoms for the past 3 weeks until last sunday when the car would not start @ all. I towed to the shop where I worked and checked spark, which was good. then I checked the pumps, no power was getting supplied to them. I pulled out the Fuel pump relay shook it and put it back on and the car started. I left it there for a day and then the problem recurred: the car would start and run for a few minutes and it would die. I pulled out the fuel pump relay and jumped the connector holes #7 and #8. The car started right away. I then test drove it with the jump and no problems. Ive ordered a Fuel pump relay and got it today. I will install it tomorrow and let you know what happened.

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"