93 pickup, 4x4, 22re, 140k. After using it for some car towing the other day (uhaul car hauler and a miata, nothing too heavy, was watching the gauges the whole time) I can't seem to get it to rev past ~3000 RPM today.

Useful information
Fuel filter replaced when I got the truck (20k miles ago)
Sparkplugs and wires replaced (20k ago).
Replaced the sparkplugs tonight as well as reading them - the electrodes appear to be brown, which I've never seen before.
Oil looks good.
No other nasty noises.

Power delivery seems just fine under 3k. Doesn't appear to be terribly dependent on engine load - going up a hill, solong as you're under 3k, is fine. I disconnected the TPS, disconnected the EGR solenoids, no change. You can floor it and it will sputter above 3k. No smoke, exhaust doesn't smell overly rich. As you approach 2700 RPM power starts to diminish. If you floor it from idle in neutral, it'll hit about 3200 RPM then start misfiring, backing down to about 2500rpm where it'll run like crap until you let off the throttle.

My guess is - fuel pump dying. I'll have to wait for the weekend to toss some pressure gauges on it to verify, but I'd like other opinions before I start throwing parts at it. I can take pictures/video if anyone seems interested. Haven't had luck finding a howto on replacing the fuel pump, but it looks like sliding the bed back a foot is the best bet, correct?

 

apologies if the video sucks, i should've cranked up the dash lights and the road noise is louder than I expected, but hopefully it gives you an idea.

 

possibly the AFM?

know anyone local that would be willing to swap parts with you for a test?

 

I've driven a volvo with a broken heated wire MAF, and while I wouldn't expect a flapper style failure to act exactly the same, i would expect <3k to suffer alot more, especially under load.

But its worth doublechecking with a multimeter.

And would still like to have a theory that ties in the towing with the failure, though things could just be coincidence..

 

mine did the exact same thing! It was the fuel pump

 

you're a brave soul. I don't think I would have the balls to try to tow a miata on a car dolly with my 22re.

 

Welp, that didn't work.

Replaced the fuel pump - nope
Replaced the cap and rotor - nope
Pulled the cat - looked fine - nope
Checked the coil - nope

Friend finally convinced me to replace the fuel filter again. And it was nasty. After replacing, went on a quick drive, revved to 5.5k just fine and I was happy.

For about 2 miles.

Doing it again, much worse now. Bucking badly, sometimes as low as 2.2k rpm. Looks like I managed to fill up my fuel tank with mud. Next weekend, looks like I'm going to be replacing the fuel filter and dropping the tank to clean it out.

 

check your plug wires one more time...in 20k they can get crispy...you never know