I have a 1996 XLT, automatic transmission. I have an intermittent engine noise that's driving me crazy. It sounds like a low pitch hum that's in coordination with the engine speed, particularly when idling. Once the engine gets over 1500 rpms, you can't hear it. It's not the water pump (I changed that already). But it's not obvious what else it could be. A/C clutch seems to work fine. Power steering and alternator seem ok. I've read that power steering pumps can be noisy. How noisy can they get? Does any one have a clue as to what my problem could be?

do a search on IAC. That's your problem.

Thanks. I found a store close to me that has it in stock for under $80. I'll perform the test on it by unplugin it when it make that awful noise first.

No problem