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If the IAC valve is clean and lubed, like you said you just did, and the throttle is clean, I'd suspect a vacuum leak as well, or the IAC is actually bad and not able to respond quickly to the load change as the car comes off A/C. The A/C provides an input to the ECU to bump idle up slightly- that opens the IAC up a little. If the A/C goes off, but the IAC hangs open a little, that would cause the surge.
If it eventually comes down to the right idle speed, then it's just responding slowly. Try another one and see what ya get.
Could need to change intake manifold gasket or injector seals as well to cure a vacuum leak.
Good luck!
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Rob Bareiss, New London CT ::: '87 244DL/M47- 221K, 88 744GLE- 202K, 91 244 181K, 88 244GL 145K
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