Although a single plug misfire is unlikely to cause the full range of the poster's issues, it is a contributing and obvious problem that should be addressed before pursuing subtler problems.

As far as things mentioned above, the sensor pot DOES affect acceleration enrichment, but it usually wears out in its default position - idle. The symptom is almost always erratic idle. Also the fuel pressure regulator holds a constant pressure - if performance at high speed is ok, then the regulator, fuel pump, fuel filter are all unlikely culprits.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7

Thanks all and thanks very much Logan_Bob. I've been sidetracked with the purchase of a 95 s124 so the 190e hasn't been getting any attention for a while.

RE: pulling vac on the intake manifold. The mity-vac is a pressure gauge .. I'm not using it to pull vacuum, I'm just using it as a gauge, not sure how to describe it exactly but if you hook up the business end whatever vacuum is being drawn registers on the guage. Am I making sense? I'm not using it to pump any vacuum, that's for static lines to test for leaks, I'm just checking vacuum pressure.

I have new hoses for the ICV which I plan to install at some point. When I do I will just dismantle the whole thing up there and check on that boot. It'll make the installation of the hoses easier and allow me to poke around. Stay tuned.

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1992 190e 2.6

Follow up for anyone coming here from a search:

Injectors.
Just did them tonight and it made all the difference. Once that was complete I installed new plugs and adjusted the duty cycle. Car is awesome now, it's all sorted. Love my car.

So it wasn't the fuel distributor, EHA or anything else .. in my case it was the injectors. Now that the car is running smoothly again it's worth fixing the timing cover leak, that's next.

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1992 190e 2.6

I called it.

Congrats on getting your car running well. Knowing you found the problem is a sweet victory. Your mpg will increase as well.

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Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2

In case anyone comes across this thread, another thing to consider is replacing the rubber seals around the injectors and the o-rings around the injector sleeves. This made all the difference in the world to my car's idle and performance. I know smp stated early in the thread that he had done the carb spray test around the engine at idle and found no change when spraying, and this would likely have turned up an issue with the seals, but I'm still curious to know if he also replaced the above mentioned seals and o-rings in the process.

If so, I wonder how much of his improvement was due to injector spray pattern and how much was to fixing air leaks. In my case I tested all six injectors into glass bottles and ended up replacing the weakest one with another used one that tested about on par with the remaining five. However, the difference in spray was not so great between the 'new' one and the rest of them, and I strongly believe that it was replacing the rock hard rubber bits on all six injectors that did the trick, not the minor improvement of one injector. I suppose we'll never know how badly smp's old injectors test out, but it sure would be nice to find out.