This is about intermittent missing.

The 400E goes unused for a week. I take it for a drive. Starts fine. Runs fine for about the first 6 miles, which includes freeway time and stop and go. The temp gage is a little over 80. Come to a stop light on a hill. The engine sputters the idle drops to about 500 and even dips below. The light changes I continue on with the low speed power drop. Clearly it is not firing on all 8. Missing is imperceptible once the tach passes about 1500 rpm. Drive it another mile and the problem is gone. On the return trip no problem. Use it the next day and the same thing happens in the same place. 2 days later, no problem. Let the car sit for 2 days. Next time I use it, the same problem in the same place? Should I just change my driving route?

Is it time for a long uphill freeway drive? I know if I take it to the shop with an intermittent problem they will never find it... The car has just shy of 80K miles on it. And had no problems until recently when it was unused for about a week. BTW I have gone many week long periods without using it in the past....

Anyone have any ideas?

__________________
...Tracy

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

First thing I would do, is check the caps and rotors, and the plugwire tips...make sure they are in good shape. Check the coils too (under the ABS box). I had my rotors and caps replaced at 87k and it was time for them to go.

Of course, there is always that dreaded wiring harness issue...

-Larry

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

Yea!! What he said. Sounds a lot like a plug wire end.

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

I support the former posts but I do suspect a possible alternative condition. The reason being that the problem occured twice at the same place during the trips.

The condition I refer to is a crack in the circuit board of the relay for the fuel pump. When the crack first completes its encirclement through the solder that holds one of the pins to the printed circuit of the circuit board... only very specific conditions will cause the crack to lose total contact with the surrounding solder. Temperature and angle of the car to gravity are the type of things that effect wheather or not electrical contact continues.

At this stage of the crack you will get the type of engine behavior described.

In time however the vibrations of driving increase the gap of the crack and the condition worsens untill the engine will simply shut down due to a total lack of fuel.

After sitting for about 15 to 20 minutes the car will start again because the expanded solder caused by the heat of the engine has by this timed cooled down, the solder contracts and contact is once again made along the walls of the crack.

The codition can be easily repaired by dropping a new spot of solder around the pin with the crack... The crack will be at a pin on the printed circuit of the CIRCUIT BOARD that runs from the male plug-in pins of the RELAY. (relay itself looks similar to pk of cigarettes with pins comming out of the bottom). The damaged circuit board pin will be on the circuit the runs from either pin 7 or 8 of the RELAY. I believe the pins are coded 30 and 78 on the bottom of the relay.

__________________
Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra

I had a very similar problem because of an O2 sensor going bad. As soon as lambda control kciked in closed loop, the car would start hesitating like no tomorrow, but after a little bit of driving like this, it all went away, then the sensor died completely and I never got into close loop.

Do some tests, do a full tune up. Post your results.

xp

__________________
1985 190E 2.3L - a constant project.

Tracy,
If you cannot find a fix/ or figure it out,I hear that the guy at Schmidt Automotive is good at this kind of work. I know a dealer who buys wrecked MBZ's and fixes them up and takes them to him for tune-ups. I believe he said the guy is in Bellevue and has reasonable rates.

Thanks guys for all the great feedback!!!! 2 more days of use and no further recurrence of the Zone. The car is scheduled for an oil change in the next couple of days and I'll will investigate along the lines generously suggested above. The car had a pretty detailed tune up at 60K – and while it included all the typical stuff, it didn’t include plug wires. Are new wires & caps implied as a likely solution?

Glmoy: I am familiar with Schmidt. He did the 60K tune up on this car. Unfortunately, I won’t be going back there. I'll share the reason privately if anyone wants to know why.

Thanks again!!!!!

__________________
...Tracy

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

uh... I wonder if you could have just gotten a bad tank of gas with water in it? get to a hill the water is able to slip in thorugh the fuel pump, not a problem after that?

cdt

GO PATS!!!!!!!

__________________
2002suzukiGSF600S
1985 190e 2.3