even after new plugs and wires our ml320 (244,000miles) experiences bucking and is non responsive to the accelerator and eventually loses all power. After sitting for 10-15 min it can be restarted and driven for 15-20 min and then we experience the same thing. This happens only after the car has been driven about 50-100 miles or so…I’m thinking of the following issues: bad fuel, fuel pump connected issues, and perhaps damage to the filter from “topping-off” the tank, which my wife always does.
Sounds a bit like vapor lock, which typically happens when the engine gets hot enough to boil fuel in the fuel line near the engine. Letting it sit for 10-15 minutes allows the vaporized fuel to cool and re-condense, you restart the engine and drive on, and the cycle repeats…
@jesmed I don’t believe sure vapor lock exists with vehicles with fuel injection.
Yea, that’s what I always thought as well. Fuel pumps being in the tank, it pushes fuel up to where it is needed in fluid form.
I do wonder if something happened to the evap part of the system that could cause this, with the tank being topped off.
Was the fuel pressure tested? Maybe it is too high.
Yes, fuel injected engines have pressurized fuel lines that do make vapor lock RARE… but NOT impossible…
Yeah, I guess it could happen.
So, Ladder, what have you tried to get it going? If you spray starter fluid in the air intake, does it want to get going again? Just trying to narrow it down to the fuel system by eliminating ignition.