i have a 99 f 350 7.3 4x4 dually
the truck has 206,000 miles and still strong. i have a bully dog, a straight 3.5 exhaust without muffler or cat and a k&n filter.runs good but when im pulling trailer sometimes loses some power. got these codes off the bully dog.
1st one was for wastegate control valve performance
2nd exhaust pressure circuit malfuntion.
what should i look for,fix or replace?

 

Welcome to FTE.

Give us the code numbers you're getting so we have a better idea. Most of the time there's more than one code associated with certain items.

Also K&N filters have been known to let too much dirt through, especially in a factory air box, so it would be a good idea to remove the cover off the air filter and inspect the tube going to the turbo for any signs of dirt or dust. The tube should be clean, and you should not leave a clean mark if you run your finger across it.

Tell us more about when you're losing power. Is it pulling a load or running up a hill? Do you have any gauges in your truck? What boost level are you running when you lose power?

 

I too have had a code come up a few times, but when my SCT XCal-2 reads the DTC it comes up as "P006a, no data". I've tried looking it up on here but could not find it. I also have had the batteries run down in the cold weather(after having the truck sit for a week) and I'm wondering if it has anything to do with that.

 

My book says MAP/MF throttle correlation