MB ML430 "Stumble"

2000 ML430 230,000 mi. The engine starts and all is fine until I hit a spot of rough pavement or a minor bump and the engine “stumbles,” feels like it has cut out or starving for fuel. I have been unable to tell whether it is left front or rear right tire or corner of the car that hits the bump and starts the engine runnng on limp home.Once it happens and I stop at a light then hit the gas, I can count to 4 before the engine responds, making left turns danerous. MB factory service since new. The dealer has replaced spark plug wires, spark plugs, crankcase sensor, gas pedal sensor and still the same problem. I think it is a loose wire or ground since it only happens after I go over a bump(even a seam on concrete any jiggle does it).Suggestions?

MB’s are known for wiring problems.
Google “mercedes benz biodegradable wiring harness”.
I don’t know if your model year is bad for this.
Is the idle rough when it’s acting up?
With the engine idling (careful around moving parts!) I would pull and wiggle any wires or connectors I could reach under the hood.


OP has a 113 engine

The 104 (4 valve straight 6) and 119 (4 valve V8) were notorious for crumbling harnesses

The 113 replaced the 119

Of course, at 13 years old . . .

Car a/c was underpowered and they replaced wiring harness in 2005. I will check it out.