Hi,

I have an idle problem.  Van starts well and makes it through cold idle but after running for 1-2 hours the idle lingers up around 2000 rpm and doesn't drop down to 750 or so in drive at a stop making the van hard to stop.  Strangely, sometimes if I let the van idle for a period at the high idle it does drop down and starts wandering around.  I replaced the engine about a year ago and initially there were no problems.  I didn't replace the oxygen sensor (original van had 87K on it) and I have a lingering suspicion this is the problem.  Also, the idle seems to wander around 400-500 rpm or so when in neutral when the van is warm.  No starting problems through.  Van does not stall.

Any votes about where to start.  

I bought Probst's Bocsch FI book and he recommends following:

Engine idles too fast

1. accelerator pedal, cable or throttle binding
2. Auxiliary air regulator faulty
3. Air leaking past throttle valve.

Jeff