Truck starting to have bad hill behavior

[Kmehr]

So recently My truck has started having some bad hill behavior, and I am suspecting the tranny. (I don't tow anything) When going up hill (mostly interstate or highway so 60+) i seems the tranny is staying locked in OD and I am losing speed. I can start a hill doing 75 put the pedal to the floor and hope to maintain speed but sometimes drop to around 65. I have had the truck for a year and a half and feel like it used to have mch more pep at higher speeds. Now I need quite a good stretch of flat road to see 85 mph. Boost is set to peak at around 11 psi and only sees that towards top of the hill. I have never seen more than about 800 degrees egt post turbo, which leads me to believe the tranny is not doing its job right.

[DmaxMaverick]

Sounds fuel related. Try a filter change. Then, have a closer look at other fuel delivery components if the problem continues.

[Kmehr]

changed it and power seems to be back for the most part, though I did not get to test it on a really long grade like I was running up this weekend. It not been quite a year since i last changed it, is this normal? I hot wired the lift pump and it is running fine. Could this be a sign of an aging IP?

[DmaxMaverick]

It may or may not be a sign of anything. If your power is back after a filter change, stop looking for problems unless you have symptoms. If you look for something wrong, you'll find it, whether it really exists or not (if it ain't broke, fix it 'til it is). There is no "typical" fuel filter life. Too much depends on too many variables. One tank of poor quality fuel can screw things up for years, and usually sends folks off on wild goose chases. This is why our first course of action is ALWAYS the filter, absent of any other outstanding symptoms. 99% of the time, that's all it is. Lower power and EGT's (compared to your "normal") indicates a fuel supply deficiency. If you replaced the filter, and the power has returned, call it good for now. Retest your original conditions when you can. If it's close to what you had before (taking into consideration the weather, and other conditions), close the book on this one.

[Kmehr]

Thanks Dmax, you're the man, I'll let it rest. I got my veg oil system back running today, went to all three classes and am already back at the library studying, so its been a pretty productive day.

[DmaxMaverick]

You're welcome. Glad to be of service.