I have had an interesting development with my 2003 F150 4x4 SC 5.4l with 32600 miles. Ever since the get go last July when I bought the truck it has had the piston slap thing going on. I hear it every morning when I fire her up to go to work, no matter how cold it is outside.

I have been dreaming of a new F250 with the 6.0l Power Stroke, but I can't get myself to take a huge loss on my '03 so I decided to start to do some modifications.

Last night I installed a K&N air filter (filter only no FIPK) and a Gibson SS exhaust. After getting it all put together, I fired her up for the test drive and all went well. A little disappointed with the sound of the Gibson, I was hoping for something a bit louder, but anyway all was good until this morning.

Before cranking her over, I rolled down the windows so i could hear what the exhaust sounded like on the high idle start up. I was happier with the sound of the Gibson, but I was really happy that I heard NO piston slap!

Is there any reasonable explanation for this? Is the piston slap related to back pressure or intake restriction? Tonight before leaving work I installed the Superchip, and on start up, again no lower engine noise.

Hopefully it won't come back, but it just doesn't make much sense to me.

Anyway, just thought I would share my experience and see what you all thought about this. Next is to find out what happens when I bolt on that KB supercharger.

Oh yeah, great site you have here, great place to come and learn.

 

Sounds weird, I wouldn't think that it would effect the piston slap, but at least it's gone