1988 300E Engine Surging Idle and Stalling

Our E300 can run fine, other times the engine Engine idle always surges somewhat. At a stop the engine can surge enough the brakes need solid application to keep the vehicle motionless. Other times the engine will
surge and die when stopped. Much work has been done to correct this problem, but to no avail. Any help would be greatly appreciated.
Thank You Brian
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Brian, join the club. My '89 does the same...... I've yet to isolate the problem. It will idle around 500 rpm roughly and then surge (the engine is trying to correct the rough idle problem) only to stall when coming to a stop Then there is a, if not literal, 'click' and all will be fine. Clearly the problem is electrical.... and probably also in yours. There's a plethora of items to chose from that could cause similar symptoms. I've heard of people selling their cars for these reasons.
best of luck, guenter

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I would want the exhaust system tested for backpressure. I am suspecting maybe both of you have original cat... and is probably clogged.
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get worse at higher rpm....? then there's the 'instantaneous' change in running characteristics ..... almost like flipping a switch ... when the engine goes from idling rough and not wanting to rev above 1500 or so (with the vacuum gauge aka fuel economy gauge, pegged at max) to running perfectly
cheers and thanks, guenter
ps I'm looking for the Hall sensor today hopefully to check
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Your perception may be "instantly" because car seems to runs okay until critical points where cat is really clogged... then it will lead to lower idle RPM as engne at lower speed has less power to push exhaust out... and that will lead to rough idling...
As for higher speed, yes, with exhaust partually closed, you can only push so much CFM out... which at that point engine will not be able to overcome that and backpressure is high.
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I started to disconect sensor to see what the effect is. disconecting the Temperature sensor from engine made things much worse to the point where engine would stall out constantly... Then (!) I disconected the O2 sensor (I'm pretty sure I got it right, it's underneath the mat on passenger side) well (!) all the sudden no more stalling.... idle still on the rough side, but no more stalling .... maybe it's just luck but will drive car again tomorrow for some distance to make sure. I 'may' have found the problem. In retrospect, I did burn oil (valve stems) for some time which may not have helped the sensor. Do you think this is possible??
cheers, guenter
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Burning oil is surefire way to plug up the cat too.
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Almost always when I have had a car surge and rev like that it has turned out to be the idle air sensor being dirty or non functional. consider checking that
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