[A1990]

I don't know if it is the same problem as what I had, but I had my throttle body enlarged to 63mm and I assume new throttle blades were installed to fit the new sized bores.

Then later I had the throttle body powdercoated.

Afterwards I experienced high idle. Mine would start off with normal idle until I drove it, but then after driving it would always idle high until I shut it off and restarted it.

I was told that the baking of the throttle body in the powdercoating process that the bores might be now odd shaped from the blades. Made sense to me that heating of aluminum could make these openings change shape.

I sent my throttle body to Marc Haibeck for rebuild and all is good now.

Did you do the test Jim mentioned or the adjustment XfireZ51 suggested. If you don't have a vacuum leak, you might be experiencing what I did.