in addition to high idle, i'm getting some white smoke out of the tailpipe...sometimes there is some when its warm, sometimes no...i also get a minor burning smell from the engine(maybe unrelated)..is this definatly a sign of bad rings, or could it be build up from this replacement engine sitting on shelf for two years?

You could do a compression test to check for a bad head gasket. Bad rings means blue burnt oil smoke out the tailpipe, which is different than your problem.

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Fast & Awesome Handling
'90 AWD
$h!tbox

Get a compression test for sure to rule out the head gasket. Do you have oil in the coolant overflow? That's one telltale sign that the head gasket is blown.
White smoke, it could be that you have bad valve stem seals. My brother's car had this happen and it was burning oil, sometimes it was worse than other times.
What's the condition of the turbo, or is that blue smoke?

Bad rings would drop the compression of the cylinders as well, and if they were really bad you would be burning a lot of oil.

Doesn't white smoke indicate a coolant burning problem?