Atlee

I have a 2014 XLT, 3.5L Ecoboost, 4x4, Supercab, long bed, Max Tow, and HDPP. When I'm pulling my 6500# GVWR travel trailer, every once in a while, when I have to accelerate hard, I get what I can best describe as a "screeching" noise. It will stop when I back off the accelerator, and then accelerate again. I'm not even sure if "screech" is the best description. It's not so much like a metallic sound, it's not a tic, it's not a knock, and it's not a "thump".

Has anyone experienced something similar? Could it be timing chain related? Or maybe not engine at all, but a transmission problem.

I would appreciate any help. The truck is going in to the dealer in a couple of weeks to change spark plugs, get new brakes (current ones are pretty worn), change the brake fluid. The truck has 52k miles on it, and I'm getting ready for a long trip out to Yellowstone and the Rockies.

StonedFX4

Serpentine belt or tensioner ???

Atlee

Hadn't thought of that. Would have thought the serpentine belt would just squeal. However I could picture a tension-er worn just a bit, and getting in a bind.

jdunk54nl

Most likely you have a warped exhaust manifold. Get the old spray bottle with soap and water in it (like checking a tire for puncture) and spray the exhaust manifold. If it is warped you should see bubbles. Note: Do this while the manifold is still semi cold so the water just doesn't evaporate.

Another check is to apply the brakes REAL Hard, and rev the engine while in drive (won't do it in neutral or park). It will build boost this way and if it makes the noise then it is most likely the exhaust manifold.