Keegan514

Hey Y'all,

New to the forum!

I've got a 2007 F150 XL 2WD with a 4.6 V6.

Over the last year my truck has developed a chirp or rattle from the lower engine compartment when going uphill. It sounds like a big washer rattling on a bolt (if that makes any sense).

Here's the kicker... it goes almost completely away with premium fuel. Every once in a while it'll come back with extended throttle uphill but it's substantially less.

any ideas?

-Adam

Turk2k5

Check your belt tensioner, they can wear out over time and the belt will slip or chirp sometimes under load. good luck

Keegan514

Thanks man, I appreciate the feedback. I'm not sure that would explain the fact that it goes almost completely away with premium gas.

Marc D

Premium gas has a higher octane used to help reduce knocking or pre-ignition/ detonation of the fuel.The valves are knocking.That is your rattle sound. BTW Not good to drive it like that. There's several things that could be happening. 1 the injectors are clogged and the motor is running lean or 2 - you need a tuneup or at least new plugs. Also try a different gas station. Water in the fuel will cause this issue. Try a can of SeaFoam in your gas. This will help clear the fuel system. Good luck.

Keegan514

Thanks Marc!

I had the plugs/coils and a fuel system cleaning a month or so back so I guess the next step might be the injectors huh?

The chirp/rattle is a little higher pitched than the usual engine knocking sounds I've heard so I've been a little confused.

I've had a sneaking suspicion the injectors might be going, I'll talk to the shop and see what they think.

Thanks man!