Several weeks ago I installed a Pro-Flow throttle body. The next day the check engine light (CEL) came on. Talked to Jim at Pro-Flow and he suspected bad throttle positioning sensor (TPS). I swapped my TPS to new throttle body but it didn't help. Tried adjusting TPS and I could get CEL to stay off but then car idled at 400 rpm and died at stops. TPS adjusted for good idle resulted in CEL coming on. Ended up returning new throttle body and reinstalling mine AND my original TPS. The next day CEL came on.

Finally got around to taking it to the dealer. The code came up PO410. After FIVE trips to dealer the problem is solved. They replaced the current sensor for the air pump-didn't fix it. Finally replaced the air pump itself and IT'S FIXED. Air pump was burned up. Apparently just a coincidence that it happened at the same time as installing the new throttle body. Weird.

Anyway the air pump is only suppossed to come on at coolant temps below 90 degrees F. If the CEL was on I could reset it, start car and it would stay off. But let car cool off and CEL would come on a few seconds after starting because the computer was sensing that the air pump wasn't working.

Hope this helps someone save time if you have a similar problem.