Stumbing/hesitation on M104 engine
 

Our 1988 300TE with a 1995 C36 engine (AMG'd M104) is experiencing a stumbling/hesitation on acceleration between 2800-3200 RPM. It also doesn't feel as powerful at the higher-RPMS.
This is a hybrid car. Think of it as a 1995 E320 W124 wagon with a C36 engine, computer, and tranny.

The car had all filters (air, gas, PS, self-levelling) & fluids (oil, ATF, diff, PS, self-levelling, brake) changed about 3K miles ago. Plugs & plug wires were changed 10K miles ago.

The car starts right up, no problem, and it feels like the entire engine is stubling/hesistating to accelerate.

No "CHECK ENGINE" light is on.

What's the proper diagnostic procedure?

Do I need to get the Mercedes HHT connected to read-off some codes?

It happenned 2-days & 80-miles after my last fill-up (ARCO Premium). Should I change out the fuel-filter?

The car has been in the rain for the last 5-days (we're remodeling). Should I check some connectors and clean them up?

Thanks in advance and Happy New Year!

:-) neil
1988 360TE AMG
1993 500E

Decided to take our 1993 500E due to the stumbling/hesitation being unsafe with the wagon.

Upon startup of the 500E, ASR light on, and car in limp-mode. Restarted 500E, ASR, light now OFF. But car hesitates/stumbles on acceleration as well!

Both cars were outside during the storm; and both cars were filled-up with gas after our latest storm but from different gas stations.

I wonder if both gas station's tank got contaminated with water . . .

I haven't found any vaccuum leaks, and I'm cleaning all electric harnesses as well.

Any other ideas?

Do I have to drain the gas tank and change filter, or is there a recommended product that will remove any water from the gasoline?

Cheers,
:-) neil
1988 360TE AMG
1993 500E

Neil- see my suggestion located at your other post in Hot Rods

good luck
-fad

Since the wagon was getting fuel at startup I had falsely assumed that BOTH fuel-pumps were OKAY.

What got me checking the fuel-pumps was that one was noisy. The other fuel-pump (closest to the gas tank) wasn't moving at all.

A couple of whacks with a rubber-mallet and the fuel-pump started working, but stopped again after a restart.

Now, do I change out BOTH fuel-pumps or just the one that's failing/failed?

BTW, since the one closest to the tank failed, I decided to drain/flush the tank and replaced both fuel-filter and tank-filter (use a 22mm hex bolt
with a 19mm nut, if you don't have a 22mm hex/allen bit).

I drained the contents of the fuel-filter into a clear glass jar and let it sit for an hour. Found fine copper-colored particulates at the bottom but
no water.

Is this normal?

:-) neil
1988 360TE AMG
1993 500E

I don't know if that engine had any wiring harness problems (sorry, my forte' is the vintage MBs), but I do know that when our '93 300E 2.8 began showing those symptoms, I wound up replacing the wiring harness and the coils. It was a known problem on those cars though. Just a thought.