2002 Ford F-150 Rattle in gear with ac on

Does this only happen with the AC on? Also, is the engine idle very low?

it does only happen when the ac is on.... as far as the ideling it is normal....

The only thing I can think of is the AC compressor may be starting to lock up placing excessive tension on the belt. I say this based on the fact you have replaced all of the components that control the belt.

that is going to be my next attempt, I noticed a little play in the powersteering pump this morning so I exchanged it... after installation if the noise persists I am sure it is the compressor itself.... will update with results

Let me know what you find. Something seems to be putting too much of a load on it.

Double check with another store if you buy a belt from oreillys!!! After the replacement of tensioner pulley, idler pulley, air conditioner compressor, accumelater, power steering pump, and belt I still had the same problem. I started to dig a little deeper into my $900 worth of receipts and decided to double check all part numbers. Come to find out the belt that oreillys has listed for my truck is about 1/8in longer than what is required. This allowed just enough slack in the belt to allow the tensioner to bounce uncontrolably when the motor is in gear at idle but, a small enough difference to dismiss as a stretched belt which needs to be replaced on comparison. At this time I am infuriated with oreillys and will be there 1st thing in the morning to have a sit down with the manager.

Wow! I can understand you frustration and demand they return the money and your old (good) parts. They won't have them because they return the core. Then, I would demand the money back.

Let me know how you make out.