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Question Strange Subtle Symptoms - Advice?
2008 Job 3 F250 w/ 42k on the truck. I have run the Spartan 210 tune for the last 35k and have recently noticed a change in the way the truck runs. Looking for advice as I have a 4000 mile trip planned for July 1 towing a 12k 5th Wheel.
Problem: Trucks seems just a bit down on power, requires more throttle to do the same things as it used to. MPG seems to be down just a bit (maybe 1 - 2 mpg) "Exhaust Leak" type noise when truck is under load and above 1900 rpm. I've been all under the truck and can't find anything that looks like an exhaust leak. I have switched to the 150 Spartan tune to test, and the noise is less pronounced, but still there.
Before these problems started I installed new Michelin LTX AT2 tires (stock size) and installed an aux in bed fuel tank. The aux fuel tank and the factory tank run through a switching valve that switches the supply/return lines along with the sending wires to the fuel gauge. The problem happens regardless of what tank I am on. The aux tank is using 3/8" hose for the supply line.
Do you think the new tires are causing the performance/mpg changes? They are factory size and not all that aggressive.
Any chance the fuel switch valve is not supplying enough volume of fuel? According to the DashDaq, I don't have any codes.
Does any of this sound like an EGR issue?
I'm considering returning the truck completely to stock and taking it to the dealer. I just don't want to end up stranded on my trip... Wife and kids will not be happy at all...
Last edited by jascott; 05-30-2010 at 05:31 AM.