I have a 1998 F150 XLT ex-cab 4X4 w/the 4.6. I use the truck primarily to haul a 21ft boat. The truck stuggles alittle while in tow. I wouldn't say struggle is the right word but, you can feel the truck working hard while towing the boat. I did a few things to help. I added the Superchip, new exhaust system and the K&N airraid style kit. It's doesn't really seem to make any noticable difference. I was considering changing the spark plugs. The truck has 35000 mile on it. I was thinging either the split fire triples or the bosch 4. I had a Ranger w/4.0 v6 and had the split fire plugs in it. The dealer said they were doing more harm than good. Which would be the best for my engine and hauling situation? Are the any other mod's I can do to help with the hauling duties? Don't want to spend too much more. Next time I'll get the 5.4. I was told the 4.6 would be fine for my use and would get better mileage. Is there a big differnce in the 5.4 over the 4.6? Any advice would be great. Overall is the 4.6 a good motor? One last thing. I only use Castrol oil in all my vehicles. What weight should I use for hauling the boat? The weather here ranges from 75 to 105 degrees in the summer. Thanks again...

 

I forgot to mention I have BFG AT tires on the truck. I believe they are 285's which I think is like a 33" tire. Should I change gears?