Well, I just tested the throttle position switch (TPS), following inthemedia's excellent directions. The engine does not have a high idle. In neutral, it idles about 600-650 warm, and warm in drive, 500 RPM.

The ignition was off for the following tests. The test between centre and the pin furthest away from the cold start injector (CSI), was continuous, it was a closed circuit. Between centre and the nearest pin to the CSI, it was wide open. Hooked up some aligator clips to the pin and put the meter near the windshield, as I pressed down on the accelerator peddle, all the the way down, no change. I used a digital multimeter, and made several tries, once on the 200, 2K, 200k and 2M ohm scales, not even a twitch.

I guess the verdict is the switch needs to be replaced? Any opinions?

Should I have tested with the iginition on, but the engine off?

Is this a DIY job? As bribenz indicated, I guess there are a few gaskets and seals that will need to be replaced when putting things back. How many hours? Any complications?

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1989 420 SEL