[CustomTruckGuy24]

Guys this is really scaring me. Ok, last December I got a gryphon and waited on my custom tune. Stock, the truck ran and runs fine. After getting my custom tune in March (87 performance) I noticed a weird pinging sound? in the rear of the truck. I really have no idea how to describe it. It's like something metallic is being rattled around back there near the tires (my exhuast exits 45'd behind each rear tire fyi). It sounded like something was making some noise back there when I accelerate onto faster roads and the highway - say 1700rpms+. It's done this since the tune and it seemed like the rotor shield on the brakes rubbing since I know the front does it at times. I've been getting more and more nervous about it and just under an hour ago I set the truck back to stock for the first time since loading the tune. It didn't do it. Guys I floored the truck. It sounded better actually and while it didn't have the same custom tune aggressive idle and such, it failed to make that noise. I tried it 2 times on stock and 2 times with my tune and only in the custom tune file did the truck make that noise. I hammered it up hills where I can usually really hear it... nothing.


So wtf is going on? I am leaving it stock until I get this figured out. I've put a few thousand miles on the tune and now I'm worried. Is it detonation? Any ideas???

[Groovy Chick]

So what did you and Bill figure out?

[CustomTruckGuy24]

Originally Posted by Groovy Chick

So what did you and Bill figure out?

It sounds like the timing and spark advancement. I had a slight feeling, but due to my lack of knowledge I wasn't positive. He said he will adjust my tune to see if it works when he gets to it. I am running stock now and there is no weird noise, but I can tell my TB probably needs a cleaning soon despite only 55k miles on the odometer. I was told by members on F-150online to run premium gas on the tune as well and see if it stops