1985 4000S running rich and sputters when cold

After replacing and checking various major fuelsytem parts I finally have the car running perfect when hot!
Here is the current problem:
When cold, engine starts immediately, but runs rough and sputters when
accelerating. Rich mixture and gasoline smell is evident.
Suddenly, after driving it about a mile, it forgets all about the above and the engine runs a smooth as butter, with very good power. Almost like a new car!
Also replaced the cold start valve. I am speculating the problem is temperature related.
Any ideas anybody?
hm
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I've got the same problem with my '89 200TQ. Looking forward to seeing what folks say.

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Might be an adjustment to the fuel distributor, maybe CO. Might be set very rich and then when the loop closes the 02 sensor compensates some for the overly rich condition. I don't see it sputtering though. (scratching head) Check the CO or FPR current when the engine is cold
Are you using platinum spark plugs in it? Try some Bosch tri-electrodes (W7DTCs) and see what that does for it. Could also be a weak coil. All new ignition pieces? New Spark Plug Wires? Might be defective but working better when they warm up.
just some thoughts! later, dave Reminder........ Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you are a mile away from them, and you have their shoes. Frieda Norris
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On 13 Jan 2004 13:47:22 GMT, snipped-for-privacy@aol.comANTISPAM (dave) wrote:

Thanks, will check on those things as well.
have to admit, that I temporarely removed the Oxygen sensor from the muffler tube and are using an old catalytic converter from my 84 junk car.
Reason for that is to avoid damaging the new converter before fxing potential fuel/ignition problems.
Perhaps I should just go ahead putting in a new converter (bonsal perhaps) and re-install the oxygen sensor which is new.
This is a California car.
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There is a set-up procedure in the 4000 shop manual to set the "quescent" setting of the fuel distributer. It uses an ammeter to measure the current to the electromagnetic "tweeking" servo in there. You might also want to check the ground lead from the engine temperature sensor as well. On my '85 4000Q, a stack of ground lugs at the battery had developed a high resistance and threw all the engine metering out of whack.
It also seems to me that an O2 sensor should at least be checked.
Gene
(dave) wrote:

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