Still tracking down cold idle issue. Car starts fine and rpm goes to 1000/min but there is a miss or rough idle or stumbling. ( feels like its not getting enough fuel )This exists until temp reaches about 60-80C then it is fine and runs like a dream with idle at 500/min.

-plugs, dist. cap, rotor are recent and I checked them again and see no problem
-new water temp sensor
-new OVP
-cleaned idle control valve(not very dirty). Pull off connector and idle increases so appears to be working
-frequency valve buzzes
-cannot find any problems with vacuum lines

have not checked cold start valve but since car starts right up I would think its ok?

thought I may have got "bad" tank of gas so I was able to fill up yesterday but so far this has not seemed to make any difference.

Would oil temp sensor or fuel pressue regulator be a culprit?

Appreciate any advice of where to look next. Thanks

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95 E420 ( 76K) SOLD
85 380SE(125k)
95 SL500(72k)

Just as it is impossible to say what it is (from a far), it is impossible to say what it isn't. But for practical purposes I would say it absolutely it isn't the cold start valve, the temp sender, or the fuel pressure regulator.

Some statistical analysis and theoretical concept would tell me that. A scope could confirm it but a statistical approach would send me looking at plug wire ends. Possibly a leaking or restricted injector/s.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Yeah, I have new set of wires coming. I figure its due anyhow since I still have the originals. However, this morning, about 25F, it started right up with no stumbling and ran fine, which has me thinking it may have been a bad tankful of gas. Only other thing I notice, and its done this for some time, is an occasional blip or miss when stopped at idle, about every 15 -20 seconds or so...very slight and probably someone sitting in the passenger seat wouldn't even notice.

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95 E420 ( 76K) SOLD
85 380SE(125k)
95 SL500(72k)

The little idle blips are almost unavoidable. When it happens on mine, I can see the oil pressure needle dip each time. It might have something to do with the way the computer responds to the O2 sensor. You can try tweaking the fuel/air mixture if you have a meter with a duty cycle reading.

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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

Update----installed new plug wires and no more cold start issues. One of the wires had a lot of corrosion on tip where it goes into plug connector. These were the original wires.

Now I have a warm start issue and from searching it may be the fuel accumulator which I will check. Today I put in can of Techron and drove about 30 miles on a the Interstate and after car sat about 1 hour it started up much better. Previously if the car sat from say 1 hour to maybe 3-4 hours it was hard to start. Guess it could also be an injector problem but I will see haow the techron a treatment does the next couple of days.

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95 E420 ( 76K) SOLD
85 380SE(125k)
95 SL500(72k)

Put in new fuel accumulator and hot/warm start problem is solved. (Hardest part of the job was trying to loosen stripped head screw for clamp around the old accumulator)

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95 E420 ( 76K) SOLD
85 380SE(125k)
95 SL500(72k)