Hello all. Longtime lurker, first time starting a thread. I've got a '93 4x4 pickup 22re 5-spd sitting on 31" tires. For the past few months I've had a problem with it bogging on acceleration, esp in 3rd and 4th gear. If I crank it cold, 1st gear is mostly okay, 2nd gear stutters, stumbles, and lurches and almost dies. But once it warms up or if I let it warm up, first and second gear are much closer to normal, although still down on power in 2nd. Regardless of warm-up, 3rd and 4th will only accept about half throttle before hitting a flat spot and refusing to accelerate further. So it'll run pretty much normal until my foot reaches half throttle, and then it bogs down and won't accelerate. It also has no power hardly going up a hill. Seems to be almost normal in 5th, but still no fan of hills (but was it ever?). All this and it still revs normally when not under load.

So far I've:
replaced fuel filter
new vacuum hoses
run seafoam through it
sprayed cleaner in throttle body
cleaned contacts on distributor cap
unplugged tps (no change except increased idle speed)
punched out cat (it was crumbling anyway and problem was before punching out—do plan to replace at some point)
new plugs and wires

I was about to try a new distributor cap and TPS, but after cleaning and uplugging those with no change, I feel like that's probably not it. My next path would be to drop the tank and check the fuel pump. It was replaced in 2016, so I'm not sure that's it, but I'm at a loss.

I also have the seemingly common issue of idle surging while the brake is applied, but it was doing that long before the current issue. I'm at a loss and at the limits of my experience. Really don't want to take it to a shop, but that seems to be where I'm headed. I've read tons and tons of posts/threads on similar symptoms, and it's flabbergasting how prevalent this seems with no clear resolutions on most.

Any suggestions greatly appreciated.

 

Any CEL codes stored? Check plug wires/coil wire for continuity? Exhaust smell rich or lean? How old is your o2 sensor? I’d say rent/buy a fuel pressure gauge and drive it around to check the fuel pressure. Sounds like higher throttle gets all the air and none of the fuel. All your injectors pulsing as they should? I’d definitely do some more diagnostic work before throwing any more parts at it. Also check your timing, you may have jumped a tooth.

 

Some of that is out of my league, but I will definitely start checking those out. And reading on how to do it. I know just enough to know the depths of my ignorance. That's why I came to the experts.

 

Google is your friend. Also go to the sticky and get the FSM for testing procedure. I had a problem similar to yours when I was quite a bit more green and like a tard I threw parts at it. Turned out being a coil wire. I swapped my perfectly good oem denso MAF for a parts house unit cause someone led me in the wrong direction lol. So yeah, just do lots of reading and learn how to test stuff. For the things I asked you’ll only need a volt meter, spark plug wire tool, and a screwdriver to listen to the injector pulse. Also yank the plugs and read them to get a bearing on if it’s rich or lean.

 

I went ahead and bought one of the electric fan kits too. I will consider regearing and found a lot of references to the Yukon ones - Hopefully it's not too troublesome for me to do it myself.

 

So if anyone has trouble with there vaf I strongly advise DO NOT GET ANYTHING BUT OEM you will have nothing but more trouble. I ended up cleaning up my original vaf and tightened the spring resoldered the contacts because I had left it outside. Put it back together and my yota ran like a champ. I spent about two weeks trying to solve this issue.