My truck is really struggling! I'm currently getting 150 miles to a tank when i used to get over 200. It also has a super rough idle, will stall out while braking or decelerating, struggles to climb hills, loses power accelerating and smells of fuel after driving. Ive replaced the fuel filter, spark plugs, rotor cap and usually put fuel additive in every time i refuel since the problem started. It only has 130,000 miles on the engine. The codes i got were 14, 25, and 26. Please help, I'm starting to burn so much money on fuel alone and I'm beginning to lose hope. I'm starting to think my only option is an engine swap. It does not have an recalls on it. i have unplugged spark plug wiring on distributor while idling and there was only a change on 2/6. 2 that changed killed the engine.

 

A quick Google search of your codes shows:

Code 14 - ignition reference signal problem
Code 25 - air-fuel ratio lean condition
Code 26 - problem with the oxygen (O2) sensor circuit

When troubleshooting engine issues I would start with the upstream problem first since it may be causing the downstream issues. The engine fires and runs so you must be getting spark in at least some of the cylinders. I would focus on the coil, distributor, plug wires and plugs. You mention a fuel smell which indicates unburned fuel. This supports the idea that either not all cylinders are firing (so timing may be way off or spark isn't getting to the plugs) or fuel is leaking out before it gets to the cylinders (bad or leaking fuel lines or injectors) so there is no fuel to burn in the cylinders.

- If you haven't checked the timing with a timing light, that is step one: timing light sensor on cylinder 1 wire, proper jumper on the diagnostic plug to disable the idle advance, measure mark on front pulley for around 10 degrees BTDC.
- You can also use the timing light on each wire to confirm spark is going to all plugs.
- Check the engine compartment and the exhaust pipe for fuel smell to help narrow the problem down.

The code 25 is strange. I would not expect a lean condition warning if unburned fuel was going out the exhaust. Maybe also check the fuel lines under the truck to the engine for leaks.

That's about all I cab offer for now. Let us know what you find.

Good luck!