High RPM and Delayed Upshifting, possibly related to P0171?

Hi all, I've spent a lot of time browsing this forum to help me fix problems. But now I have an issue that I can't find answers for on my own. I drive a 1998 Tacoma 2.4L 2RZ-FE, about 205k miles. Automatic transmission (4 speed?). Long post incoming, it's everything I know laid out. Thanks.


My truck gets to pretty high rpms before it shifts up. It's like if I was driving a manual and waiting too long to shift basically. The shifts seem very tied to the speed I'm going, and not so much tied to the load. For example, it shifts to 2nd at 20mph, 3rd at 40, and 4th at 55. I'll call this "Bad Setting".

I've never driven a slipping trans, but from all the videos I've looked up this isn't slipping. The engine feels nicely engaged the whole time. The shifts feel pretty normal, sometimes a little jerky; doesn't seem effected by accelerating hard or softly.

However, when it gets close to the shift point (say 30-35mph), and I let off the gas to coast, if I get back on the gas, it seems like the engine has to rev back up before it engages/accelerates.

IT GETS WORSE. I was going up a long hill, and when I was passing a truck I stepped on the gas a little. Ya know when the engine goes into like overdrive to get going (is it dropping a gear when that happens?), well that happened fine. But then it wouldn't get back into 4th gear. Slowing down and speeding up showed me that the shifting speeds (mentioned before) seemed to be increased. Restarting the engine didn't change anything. I'd have to get up to 25 to get into 2nd, and almost 55 to get into 3rd gear. I couldn't get it into 4th at 75, and I didn't feel good pushing it any harder than that in 3rd (getting into 3rd at 55 feels really scary already). I'll call this "Worse Setting".

At that point I was 200 miles from home, and was able to get rides for a few days before I had to return. On my way home I got into 3rd and kept it at max 65mph. After a long stretch, then a couple red lights I stopped for the bathroom. And when I started it up again, it was back into "Bad Setting". It drove like that for a few weeks.

It happened again after I was driving for maybe an hour at ~70mph. I slowed down to around 60, and it dropped into 3rd and seemed to change itself into "Worse Setting". It is currently in "Worse Setting".

One random time I was getting up to speed on the freeway in "Bad Setting", the temperature gauge spiked, went back down, then spiked again, and slowly went down. I had never noticed it doing that before of after again.


What I've tried to fix it.

For the shifting, (this is after it fixed itself from "Worse" to "Bad") I've checked the atf levels, and it seemed normal, although kinda brown. So I removed the drain bolt in the transmission pan, and then replaced the amount of fluid that drained. Drove for a week, and did the same process. Roughly 2.2L replaced each time. This seems to have done nothing.

Unrelated (maybe??) I have a P0171 code (lean fuel). This has been on for about a year (I know I know), but hasn't seem to be an issue ever. I've replaced air filter, sprayed the MAF sensor, tried checking for vacuum leaks, and replaced both O2 sensors. Nothing has helped so far.

Before I had a P0171, I had a misfire. I found that a fuel injector was no longer firing (after replacing all spark plugs and wires with Denso). I replaced the all injectors with some ebay injectors, they seemed to fix the problem. No misfires that I can feel right now.

Also I have a small crack on the top of my radiator, I JB welded it a few years ago. And just recently it cracked through the JB a little. Only leaks a little, and I add some coolant here and there.


On a budget, trying to fix this myself. Not a lot of car experience, but healthy amount of wrenching experience. Thanks for all the help. Currently have a OBD bluetooth dongle in the mail so I can look at the live data (and try to make heads and tails of it)

 

Talked to a shop, and despite being weeks out on even a diagnostics appointment, he gave some useful advice. Mainly, that it could be the throttle valve cable (kickdown cable/ TV cable). It seems to not be retracting. I've tried adding lubricant to the cable and housing, but so far to no avail. I've got it all unhooked (except at the trans), and I'm going to try adding lube from the trans side of the cable and loosen it up. But that probably won't help if it's heavily corroded or frayed.

Does anyone know if I'll have to drop the pan completely to replace this cable? Or is there some kind of hook that sticks up near the port? I think I already know the answer, but I'm looking to get around making this a larger job than it needs to be. At least for now.

There's also a nice electrical block of something in front of the cable port into the trans. Anyone know what that is? Kinda blocks my vision and access to everything. Can I pull that off without fluid going all over?

I'll keep updating.

 

did you fix this yet?

 

Yeah .....you have to drop the pan to get to that cable.....

but its not that bad.....


And yeah a lot of times when messing around with that cable....it can get hooked or jambed all the way out...
....you can gently wiggle and coax it back down and in...

If that cable in engine compartment is jacked or routed any different than original.....you get weird delayed shifting...

I shifted that cable couple inches away from stainless headers I put on....
and that was a no go...had to insulate and put back 2in over....crazy...

Also there is a overdrive solenoid that can get stuck.....if fails it would stick in overdrive off mode....
so a warning do not use the overdrive cutoff button.....when solenoid fails....it fails in off mode ....giving you only three gears...
If you dont ever mess with it.....then it cant stick in off mode.....

I believe last time I checked that solenoid was $420......and only one in country...
others were in Dubui...

 

So I now have a new TV cable installed and the taco is working correctly. In case anyone needs a similar repair I'll write up my whole process.

The TV cable is easy to disconnect at the throttle valve. And there's 3-4 hooks it slides in/out of as it routes down toward the transmission. There's also one bolted in clip near the bottom, it bolts on to the top of the transmission? body. Kind of a pain to get a 10mm? in there to remove it, but not as bad as getting it reinstalled haha. I was able to reach up from the bottom, only bending my arm in a few unusual spots; I used a regular 1/4" ratchet, but some fancy flex heads might have helped.

At this point there's two main steps left. Get the plastic "plug" that's a part of the TV cable housing out of the transmission body, and drop the transmission pan to unhook the cable end of the TV cable. (and putting the new cable in)

I dropped the pan next. Drained all the fluid from the drain plug then loosened all the perimeter bolts. Some light tapping with a hammer was able to break my seal pretty easily, and some very light flathead screwdriver-ing to pry apart the parts that were a little sticky. I loosened the bolts accordingly to allow the fluid to flow toward the drain plug and drain even more. Then removed all the bolts fully and dropped the pan completely. There's a good number of videos on dropping the pan out there, probably all the same general procedure. They also go over cleaning the pan, scraping the old gasket off, new gasket install, etc. I'll skip over those bits since I'm here to talk about kickdown cables. (Oh yeah, at some point you'll want to remove the dipstick, and loosen the upper dipstick holder piece to allow a more easy pan removal)

NOTE: there's some nice rails inside the transmission that seem to make it impossible to change the filter easily. I was loosing daytime light and wasn't prepped for that, so I did not change the filter. Just take note of that, in case you want to buy a filter to change while you're in there, like I was. (Anyone looking for a filter and filter gasket?) Luckily I didn't notice major particles in the bottom of the pan, so we'll leave it in the hands of higher powers.

Getting the cable/housing removed from the transmission was the hardest part for me. When the pans removed, on the passenger side, you can see where the cable feeds into the trans and hooks into a little cam-like device that pushes a big silver button. My TV cable was stuck/frayed in the open-throttle position, meaning I had no slack to work with in removing the cable. (The device you're removing the cable from, is pretty much identicle in design to the one at the other end at the throttle valve.) Unfortunately it's pretty much required to have slack in order to move the cable perpindicular to where it hooks in, in order to remove it. So you're going to have to make slack, either using pliers to yank that cable back down, or using some kind of leverage (screwdrivers?) to help spin the cam back into a relaxed position (as in using the cam to yank the cable down). No easy way around this.

Next hardest part is the plastic plug on the cable housing that plugs into the trans. It has 4 prongs that help it clip into the body. Removing it is a pain. It's pretty far up from where you can reach it, need some long needlenose pliers. Squeezing all 4 together at the same time is near-impossible, and even some tough pulling on the housing from above doesn't seem to help much. I ended up resorting to using pliers to snap the prongs off from the inside. I wanted to avoid this, as I was real afraid of getting plastic shrapnel inside the trans, and there were places it could have fallen/flew to I wouldn't be able to see or reach to remove them. Luckily the seemed to break pretty clean, and I was able to recover 4 large chunks of prong that I snapped off. From there I was able to pull on the whole housing and remove the TV cable with a little screwdriver help. Getting a flathead between the trans body and the shoulder of the plug helped break the seal a little (little O-ring in there makes a tight seal). You can get a good visual of where to flathead from the back side of the car. Gotta shove your head up there real good at the right spot, and you can just get a direct line of sight. One hand on the flashlight, one hand getting a screwdriver in just the right spot to help pry, one hand pulling the tv cable upward, and one hand supporting your body for all this core workout you weren't expecting. Or maybe you could just buy a lift and save a little time.

From my earlier post, there is an electrical doodad sitting right infront of where the cable plugs into the trans (speed sensor? rotation sensor?? IDK). Loosening it helps with manuevering the old plug out, and new one in. There's a 10mm? bolt facing the passenger direction that you can loosen up pretty good without removing. However, the doodad seems to have some kind of variable position depending on where it gets tightened down at. So you might want to clean and mark (sharpie/etc) where exactly the doodad aligns with the bolt you're loosening. I was able to use the dirt and grime as a mark of where it was tightened before. Maybe it matters a lot, maybe not at all. Maybe if someone else reads this longass post, they can chime in on what it is.

Once everything is removed, putting the new one in is pretty straight forward, mostly just reverse of taking it all out. The plug goes in with a nice click. Hooking the cable into the trans a little tricky, gotta rotate the cam-thing against the spring, hold it there, and hook the cable into it. I used a pick to kind of walk the cam in the direction I needed, using my finger to hold it in place until I could reposition the pick to walk it a little further. Little frustrating but kinda straight forward. Then I routed the TV cable back up to the throttle. Made sure it lined up right and clipped in to everything before I closed up the transmission pan. Add in the appropriate fluid level, etc.

The next hardest part was getting the tension just right on the TV cable. There's some nuts on the threaded end of the housing that allow for loosening/tightening the cable. Too loose and it shifts too early, too tight and it shifts too late. I went on a few low-speed test drives messing with tension until it felt dialed in. BUT I don't have a definitive method of knowing if it's exactly right or not. Does anyone know??

I've put a few hundred miles on it since the repairs. It feels pretty solid. Overdrive kicks in just fine when I'm gassing it up a hill, and more importantly, it turns off! I've got all 4 gears working good. There's some very slight tweaking I might make on the cable tension, but that's about it.

(Since then I've replaced the leaky radiator. And had a surprise visit from the broken starter fairy. Always something huh?)