Throttle related question on my 93. It runs beautifully and no issues when warm. But when cold, I get what I can only attribute to a sticking throttle.

At cold start, it idles low, like when the EDS Is not controlling the throttle properly (I am getting a code reader device so that I can check out all the systems). And idles around 550 RPM for the first few minutes when cold. That’s not really a big issue to me as I can probably figure that out, the bigger concern is that when I hit the throttle it sticks. For example if I want to move the car and I might take this engine speed up to 1000 or 1500 RPM, it will stay up there after I take my foot off the throttle. If I am trying to maneuver the car, going backwards and forwards, the RPMs will shoot up over 2000 RPM.

Because everything is so tightly packed under the cowl in this car, it is hard to see what the issue might be. Again, it does not happen once the engine is slightly warm. I would think that if it was something gunked up, or dirty, that it would always be sluggish to return. But that’s not what I see. Any recommendations on how to diagnose and potentially fix this?

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)