I have a 1996 f350 4x4 reg cab, 5spd truck, 410 gears 265/75r16 rubber 112k miles on the clock, 2 owner truck, xlt, and I feel that it is slightly lacking power when towing or climbing mountain passes. Not significant, but noticeable. I have driven probably 5 of these trucks all configured similarly, and mine is not as powerful as the others feel. While towing, nothing serious, like hauling a 18ft boat, a gooseneck with a pickup on it, small trackhoes, campers, the like, cargo under 10000lbs, it seems to be lacking in power.

Empty, it seems fine or atleast comparable, but point it at a mountain pass and you wear your right arm out before you get to the top. Fuel mileage seems reasonable, 10-13 empty.

What I know:

New fuel filter
New plugs and wires
new cap and rotor
Free flowing exhaust
new air filter
Runs smooth
starts easily
runs at the 190 range
Timing seems to be unmolested @ 10*
brakes aren't dragging
Fuel pressure on rear tank good, front tank slightly lower, weak pump, still in spec
O2 sensor is original, and voltage is consistent but low. Possibly from me being at 6000 ft, possibly bad sensor, I have consistent battery voltage at the sensor.
Cat delete, and air system still intact just blows into exhaust now.

My questions are fairly direct, will the O2 sensor map it's voltage for higher elevation and drop voltage significantly due to the need for leaner mixtures? My voltage was about .18 volts respectively engine warm and idling.

Could there be a fuel injector issue, like dirty, faulty, or just worn out? possibly need 8 new injectors?

Would a timing chain possibly stretched enough to hurt the performance? I am aware that this generation 460 has a good timing set from the factory, but nothing lasts forever. Thanks and hope we can help my truck to live and breathe another 18 years!

 

Also, No stored codes and no CE light.

 

That's most of your "problem" right there, you lose 4% per 1000ft above sea level so your 245hp motor is down to about 186hp at 6k.

How are you measuring O2 sensor voltage? It's a dumb device that produces a voltage that switches rapidly between 0 and 1v when the engine is in closed loop(idling in park) and you need an oscilloscope to see this a DMM won't work. These things don't last forever so if yours is of unknown age change it out, a tired sensor could make the engine run a bit lean but in most cases when it fails the computer stays in open loop all the time and gas milage suffers but power is usually unaffected.

 

Greatly appreciated. I pulled codes again and got only system pass. As far as elevation, all of these I have driven were here and higher. Telluride gravel in Telluride, CO used to buy between 2 and 6 of these trucks every year new, f350 reg cabs, 5 spd 4x4 410 gears and 460s. The only one that was different was a 93 superduty with a 5spd 2wd and the 488 or lower gears. I spent a lot of time in those trucks,and all at higher elevations in the mountains. I never felt that they had less power. I felt that they were more powerful or atleast as powerful as mine. My truck feels about like my dads old 83 f250 with the boat anchor 460 and an auto and 410 gears. Maybe I just remember more power but I want to do an O2 sensor and see if anything changes, Thanks.

 

When you checked fuel pressure, was it idling or under load.
I had one truck that was 42psi idle and revved up, but under load it went down to mid 20s.
If you don't have a fuel gauge then pick up a cheap oil pressure gauge kit. They usually have the correct 1/16th pipe fitting for the fuel rail. Zip tie the gauge to windshield wiper to see it.

My truck liked having 48 psi base pressure with vacuum disconnected. Used an adjustable regulator from a mustang.

 

I think this is a problem. The front pump was lower than the rear pump, slightly, and the check valve in the front tank is bad, is actually bleeds fuel from the rear tank to the front tank. I am betting that the fuel pressure is actually dropping under load and the engine is starving, thus displaying a low power condition, my tests are all idling. I am a Matco Tool distributor, so i will put a FP guage in my order and go from there. I was reading and I hate to molest my truck, but the gains from all the bolt on mods have me really curious as to what I can actually get out of my old rig. Thanks guys.