I got the car to start (87 300E) and I'm trying to track down the rough idle now. What's been done:

cap/rotor
fuel pump relay
ovp relay
determined there is spark
eha 1/4 turn clockwise
icv swap w/ known good unit
checked breather lines - all look good
swapped little button thingy on throttle linkage
enriched mixture - no help
leaned mixture - no help

Symptoms:
under idle (eg in P, R, N, D, 3, 2 w/ no gas pedal applied), the engine runs at around 500rpm (used to run at 700-800 rpm) with the vac gauge (economy gauge) above the lowest point. Engine sounds like it is going to stall, and sputters out when throttle is first applied.

Question:
Can I trick the system, as the idle is fine when slight gas pedal is applied, by manually increasing the throttle's starting position to have some throttle applied, or does that little click box thing need to be applied in order to start the car? Are there any other vac lines that should be inspected that could pos be related to this problem outside of the 4 breather hoses? What else can I check to determine the source of the rough idle - fuel delivery is fine, spark is fine, air is fine, and the car runs fine under load?

Thanks for your help.

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87 300E
202k on the clock