OK....I've been following all of the threads on hesitation/rough idle problems.
I appear to have the "classic" symptoms". Cold start rough idle, poor acceleration from stop, etc.
This evening in an attempt to do some troubleshooting without the use of test equipment, I warmed the car up - drove perfect with one exception (hard stop followed by poor acceleration) then disconnected the EHA valve.
Car started very rough and any and all acceleration was very poor. It appears that my condition got worse.
So, the question is (without the use of any multimeters, etc), is the EHA valve functioning correctly?
I did notice some weapage on the underside of the EHA valve from the 2 holes in the valve.
From previous posts by others I have the impression that by disconnecting the EHA valve, conditions improve, thus there is a potential problem with the EHA valve.
I do acknowledge all of the recommendations previously posted for continuing troubleshooting directions. I've already changed plugs, rotor and cap and will seriously consider the ignition coil. The coolant temperature sensor checks out ok, although the temperature meter sensor is questionable.
Thanks for any and all input.
1991 300CE 108,000 miles