Isn't the fuel rail on the '98 held down by just a few bolts? It couldn't have been as bad as my fiancee's old Sebring that the back half intake manifold had to be removed to get to the back plugs. It took me an afternoon to get back there and sew her up, but it was the first time it had to be done in 150,000 miles.
I'm not making this a Ford V Chevy debate, but rather sharing my experience and frustration. I have included ONLY my experience, not the experiences of people I know or things I have read.
It was a MAJOR PITA. It took several extensions on a 1/2 to 1/4 drive ruducer to a swivel to a 7mm socket to get the #4 (passenger side rear) Coil On Plug off. The fuel real was easy enough to get off after you take the engine cover off. The real problem was on the fuel injector o-rings that would fly off and into the open intake manifold razor chasm. Of course above the #4 plug was all the coolant lines for the rear a/c making it a job for someone with the hands of a three year old on the arms of someone 8 feet tall.
I traded it in for a 2003 Suburban and couldn't be happier. The chevy/GM 5.3 is a (in my opinion) a much better engine, is easier to maintain and had more HP and torque for that model year. Also everything still works and I have nearly twice the mileage as I had on the expedition. On the expedition the A/C worked but the "blend door" that was evidently what the truck was built around was broken so it would only blow out cold air, which was awesome in July from Dallas to New Orleans, but that same drive in December meant that in order for us to have heat in the rear, the front air conditioner had to be on too and since the blend door was stuck on cold the front basically froze and the rear melted under hellish heat.
The Explorer had even more issues with my wife having to stop while giving it gas so it wouldn't kill due to the SOHC V-6 EGR valve/sensor (I may have the name wrong, this was back in 2002) constantly getting full of carbon and reading incorrectly. On
both the Expedition and the Explorer the wipers would only work sometimes and at the speed that they wanted to work at. The radio was integrated into the steering wheel which was cool but the display didn't work due to some improper heat sink solder joints that failed all the time. (the radio would get incredibly hot)
All that and the Rubbermaid interiors ruined me on Ford forever. The only vehicles that Ford makes that I would consider buying is the new Taurus and the Mustang.