I've a 2006 crew cab F-350 , 5.4L .

So while going down the highway, between 60-70 MPH, just cruising, I have heard a weird exhaust noise a few times a minute, for a second or 3, like the exhaust is being restricted. I didn't give too much though to it, until I got a OBD2 reader for android, because occasionally the speedometer reads high by 10-20 MPH, and when I sit still it shows the 10-20 mph offset. I get the Torque (lite) app, and see that my speed is right on the OBD2 bus, but at the same time, I'm noticing that my throttle position, about 17 at idle, and 20's when I'm on the highway, at speed, spikes to 70 each time while the weird exhaust noise happens. So, it's not exhaust restriction, it's extra gas being dumped into the exhaust, as throttle body isn't supplying 70% air volume. I was thinking - simple, the TPS has a bad spot in that area, so I replaced it earlier today. When I test it out on my commute into work a few hours ago, it's still doing the same thing. Does anyone if there are other sensors or something in the computer that might be doing this? Thanks!

 

Welcome to the site John

What year and engine?

 

It's a 2006, 5.4L. Updated the OP as well, thanks