Underpowered 98 L-D F250

I purchased a used 1998 F250 Light Duity pick up to haul my 30' travel trailer. I live in Michigan but the truck has Calif emissions pkg. It does OK on a flat road but lacks power to keep speed going up even small hills. My trailer weighs about 5000 lbs and I'm thinking the truck should be able to handle it. How can I maximize torq & hp without dumping a lot of money into it? I only pull my tlr 6~7 times per year and can't justify expensive accessories/changes.

Does it have the Class V towing package? I'd bet not, since our 4.6L auto equipped F-150 SC with that package did just fine even with over 7500# in tow. Great, no way. Fine, definately!

What motor do you have? Some things would be dual exhaust with an x-pipe, cold air intake, and a chip.

Does it have the Class V towing package? I'd bet not, since our 4.6L auto equipped F-150 SC with that package did just fine even with over 7500# in tow. Great, no way. Fine, definately!
- It came with a class V hitch and an under-dash tralier brake wiring harness. It has a 5.4 engine with 108,000 miles.
My engine light came on last summer and I had to replace all the plugs and 2 bad coils. A couple of months ago it came on again and I had to replaced both upstream O2 sensors. I'm wondering if something is wrong with some other aspect of the engine/emissions control features.
- My dad has the (non-calif) 1997 version of the same truck and he says that his tows just fine. He can even pull his 28 ft 5th wheel in overdrive. I have to run mine in 3rd gear and keep engine at 3000 RPM.
- I've spoke with on other person who owned the 1998 and he was pretty dissappointed with his as well. I'm wondering if the 1998's had a bad design or faulty component.

What motor do you have? Some things would be dual exhaust with an x-pipe, cold air intake, and a chip.

I have a 5.4. I was thinking of doing something along those lines but I don't want to put all that money into it just to get marginal performance improvements.