86 420SEL cold running problems

[kdlemon]

hello everyone.... my 420SEL has developed a problem. i have read the recent thread relating to an unfortunate fellow's 420SEL hot running problems.

my problem is very similar except it exists when cold. idle is good under all conditions, and it starts quite easily either cold or warm. after it has been running for a few minutes, it accelerates cleanly and smoothly as expected (perhaps a little low on power, though). when cold, however, if one jabs the throttle, it will gasp for air, backfire through the intake, and stall. if one depresses the accelerator in a smooth motion, it will bog down (it seems like a lean condition) and backire/die unless one quickly removes one's foot from the accelerator, at which point it usually idles.

when cold, the car is undriveable, but after a few minutes of running, the car runs perfectly.

i have played with a few things... taken a few measurements with a multimetre... but i'm not that sure what i'm doing. when i rotate the throttle pot, nothing happens (nor does it matter whether or not its connected). the running of the car remains the same whether or not the pressure solenoid is connected - but resistance at the loom plug changes as temperature increases.

really the car seems to respond as a plain jane CIS car would respond... could it be that the pressure solenoid is faulty? or does the throttle pot also control the idle solenoid?


thank you, kaydee