I did a search but haven't read a post w/symptoms that my car has.

Car starts and runs fine in the morning, but after it's warmed up it develops a low surging idle and hesitation on acceleration. Some times it's so bad it'll stall the car. Car will restart, but only after some difficulty.

Things I've changed (for new parts) previously for idle problems in the past.
2001
Rotors
Cap
Spark Plugs
Wires

2002
OVP

2003
alternator
Found a loose vacum hose

2004
Nothing

2005
fuel pump
fuel filter
temperature sensor
injectors cleaned
spark plugs
ignition coil
...new idle problem this year is frustrating me. I've already spent appprox $500. I'd hate to continue to throw parts at it randomly. What should I try next?
Oxygen sensor? (Has anyone tried the Ford replacement?)
Fuel pressure regulator?
MAS?
ICV?

Please help....

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JR
1986 Gold 300E 4Dr automatic

Not sure on your model but on my 380SE I had bad ignition control module. Car felt like it was "missing" on take off and also stalled a couple of times. Unfortunately this is about a $300 part(rebuilt)

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

Well, a worn airflow meter potentiometer will cause problems at idle and off-idle acceleration, if performance is pretty normal once you get the rpms up. Reason is, this is the range where the wiper spends most of the time, and the element wears thru. If you disconnect the pot's plug, and idle steadies out, this is the problem. Part available from Bosch (check past threads) or with the whole airflow meter from MB sources, if you're rich.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7

I would pull the icv valve...and give it a good cleaning with brake cleaner....better yet, if you can let it soak overnight.

wouldn't cost you more than a couple of bucks.... watch for brittle hoses connecting the icv

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1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

hmmm...so you guys don't think it's the O2 sensor or the fuel pressure regulator?

I think I'll try:
1. Cleaning out the ICV (no cost...except brake cleaner, hopefully relatively easy to RR)

2. then I'll replace the airflow meter potentiometer ($80). I did a search and found the thread. I'm not too familiar with setting the .7V using a voltimeter (sbourg, can you explain that portion to me in "lay mans terms". Please give me "idiot free" step by step instructions on how to attach and read the meter. Pics would be great!)

3. If that doesn't work, I'll change the O2 sensor ($40 Ford replacement)

4. igniton module (Ouch....$300??!!! Hopefully I don't get this far)

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JR
1986 Gold 300E 4Dr automatic

Pull the passenger side front carpet and check the O2 sensor connection.

Good luck,

Regarding the air flow potentiometer: try
http://www.europartsdirect.com/
They sell it for 45$.

Good luck, Bruno

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1992 300TE 160 kmiles