whistling/rattling sound when accelerating
2004 f150, 4x4, 4.7 litre, makes whistling/rattling sound only when accelerating, going up a hill, or under load...sound like its coming from engine area, passenger side? hard to tell...
Could be a pulley, bearing, vacuum leak, etc. See if you can recreate it in your driveway. Put the car in park and have someone rev the engine while you inspect under the hood. Maybe place the car in drive and foot on the gas gently.
Exhaust leaks come in many forms: Pinhole in the tubing, cracked nipple for the EGR, loose EGR tubing, Rotted muffler, cracked manifold - most muffler shops would be happy to look at it and give you an estimate of repairs for little or nothing.
Check the hose coming from the IAC valve to the air horn, Had to replace them before for that cocncern.
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