Losing speed after driving a while...

[Freshmeat]

Here's what happened:

Drove about 20 minutes and it started stumbling/bucking badly if I tried to force a downshift by bumping the throttle. After about five minutes of this I couldn't get it over about 40mph. Then 30. Then I couldn't touch the gas so I pulled over. I figured it was the fuel filter so I went to the store and replaced the filter. Car sat a total of 45 minutes but ran like a top with the new filter.
Drove 15min to the old house, car sat another 20 minutes while I loaded boxes.
Driving back to the new house after about 20 minutes it started bucking if I hit the throttle again. I had to idle the last mile home.

[grandpaslincoln]

TFI overheating?

[gadget73]

TFI overheating?

That would be my vote, or the coil getting hot and dying.

[Freshmeat]

Only the coil isn't new. I'll order a new one for peace of mind and hope for the best. I won't give it much effort before I take it to someone. I don't have time for this. At least it gives me an an excuse to DD the Explorer, which has A/C.

[Danny_R]

This might be a long shot but check your wires going into the coil, the two small gauge wires. The clown I bought the car from had tried wiring a Tach and had made a really crappy job at splicing the wire to the coil. My car did exactly the same thing as you described. He'd cut the wire and reconnected it with a crimp on butt connector. The connector was all loose and corroded. I stripped back the wire and soldered everything up. Checked and everything worked perfectly.

Have a look at yours and make sure the wires are nice and secure/free of corrosion.

[Freshmeat]

I replaced the coil with a new stock replacement. At the same time, before a test drive, I went to cut off the A/C belt because the smog pump makes a whole lot of noise. In doing so I discovered that the battery to block ground is rubbed almost halfway through from contacting a belt. Going to replace that some day this week then see if those two things fix the problem.

[gadget73]

Another thought because of something Ryan told me this weekend. Does this still have converters on it? If those clog really bad, it will make the car into a gutless wonder. Most of the time, they only clog like that if an injector or two are shot and pissing fuel like mad. Black spark plugs on one or two cylinders would probably be a good clue

[GM_Guy]

Converters would be my first suspect. Hotter the car, the worse it gets, eventually it'll just be sluggish all the time and start blowing oil out of every crack.
Dropping the pipes at the manifolds will be your quickie test to see if it is an exhaust restriction--keep in mind this isn't something you can do in town due to noise, but if you are located somewhere out of the way it'll be easily accomplished. Take it for a spin on the same day, full throttle acceleration, cruising, etc. Drop the pipes (wire them up to keep from destroying them) and take it for the exact same spin. If she is alive again (you will know it) your cats are likely plugged (or somebody shoved a bunch of crap down your tailpipe).

Alex.

[Freshmeat]

I'd be fine if it's the cats- I have an offroad H-pipe and most of a 2.5" exhaust; just need to get the missing parts and I can toss it in.