I'm having an acceleration problem and occasional rough idle in my 87 300E. The car will go totally listless with little to no power at all under normal acceleration. If I totally step on the gas and open the throttle all the way, it will take off like it should but for 2-3 seconds, it acts like it just isn't going to go.

I've checked the plugs, distributor and rotor, wires, etc. and nothing has changed. I've seen several threads about air flow sensor problems, O2 sensor, throttle actuators, etc. Which all seem to be possibilities.

What I'm trying to do before I throw parts at this thing is to check the codes. I can't figure this out. I see Arthur Dalton's homemade tool to check the flashes, but where are the pins on my car??? The only thing I can find is on the drivers side fender, a small round deal with 9 pins. Is this it? The banana plugs indicated from Arthur don't fit in this thing (too big) so I'm thinking this isn't it?

Any help would really be appreciated.

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Ty H.
'87 300E 135K Miles