Lazy Throttle on Warm Up

[RykBoeh]

I'll preface this post by saying I'm very new to vanagon ownership and fairly new to working on vehicles so bear with me.

I'm having an issue with my '85 vanagon (2.1 automatic) where my throttle response stoops at idle when the engine temp is between cold and normal running temp. It is fine after start, and once the engine is a fair bit warmer, but in between it refuses to come off the block if left to idle (at a stop light or some such). The weirdest thing is that if the engine is restarted, the issue retreats for a while until left to idle again.

So far I have tested the temp II switch which, while slightly off base, seems to be fine enough. I've swapped out the ECU with a spare to no avail. The van actually smogged to my surprise, and when I asked if the engine was running lean, was told it actually ran on the rich side if anything.

If anyone has any ideas what could be the cause, I'm very interested to hear from ya! Thanks so much!

[blackglasspirate]

The temp II would be one of the first suspects, though you've said you've already testing that. I'd test again from the sensor itself and from the ECU harness to be sure. It's a cheap/easy enough thing to replace anyway to be safe.
Other than that the first things that come to mind are the O2 sensor and the TPS. The O2 sensor doesn't kick in for a short while after the engine is started, so maybe it's causing problems between the cold and hot states of the van. You could try unplugging it and seeing if it makes any difference.

The TPS adjustment is also very important and can cause idle issues or just off-idle issues, though the temperature of the engine shouldn't matter. Either way it's worth a check. The digifant pro training manual (google it) has the full troubleshooting for it, but you can hook up an ohm meter to the throttle position switch (TPS) sensor and manually open/close the throttle to make sure it's functioning correctly.

That's where I'd start, but I'm no expert!
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