Please I need some help with a hesitation with a 91 300SL (129 with 104 engine I think)
First lets get this out of the way. I have a shop which specializes in electrical and Computer systems in domestic and asian cars. I do not work on MBs except my own and a couple of friends. So I sure could use some help on this one.

We are the 5th shop to get this car. One was the dealer and no one has been able to fix the problem but each has made money by throwing parts at it.

Here are the thinge I know have been replaced
Coil, wires, plugs, cap and rotor
Fuel pumps and filter and fuel tank cleaned out
Fuel pressure is 92psi and still at 45psi after an over night sit. Fuel pressure remains at 92 psi during the hesitation.

With the help of this wonderful forum and lots of reading this is what I think is wrong.
I have checked the airflow pot for proper operation (.68V at idle increasing to3 to 4 V with acceleration). EHA current at 0ma after adjustment and varying.
I think I understand that the EHA current should INCREASE when accelerating. Well, it DECREASES. Does any one know how this could happen?

By the way, the car idles great at about 700 RPM, accelerats fine if starting off normal and runs smooth at speed. The problem only shows up apon HARD acceleration. After the engine gets past about 2000RPM everything is fine again. It feels like an accelerator pump not working in a carb. My understanding is that the increase in EHA equates to the accelerator pump.

Thanks for any thoughts on this problem.

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84 500 SEL (307,xxx miles)