Team_Jake, I am in the middle of dealing with an extremely similar situation as yours. My gauge issue started after plugging in an incorrectly wired trailer (which is very similar to another poster on this forum). I went through the same evolution as you, where I found some suspect tail light bulbs and replaced those to no avail. Much like the other poster I mentioned, I also discovered that when I plugged in my now correctly wired travel trailer, the gauge works correctly and accurately. When not plugged in, the gauge reads as full for few moments, then drops to absolute bottom and the fuel light blinks.

I'm not an expert on this, but after gathering every incident of fuel gauge problems on 3rd gen 4runners I could find on the internet, I felt that while a large portion of them were due to the instrumental panel "recall" and/or a faulty sending unit, a smaller subsection of them were not due to this. Of these, the only common theme I could see for those that fixed the problem was electrical ground, most typically associate with the tail lights or trailer attachment wiring. I noted that it wasn't always a broken ground connection, but in some cases insufficient ground (i.e. larger gauge wiring, or more robust connections solved the problem).

I have just begun a process of checking every ground point on my wiring diagrams starting with the closest ones to the trailer wiring and taillights. Unfortunately, some very cold weather around here stalled the process for me and I hope to continue to process when it warms a little. Please let me know if you solve yours, and I will do the same...and any other readers as well!

@SeaBass5000x

I believe I solved it. Earlier, I tore apart the rear side panels near the tail lights and checked the ground wires. All looked good. I then opened up the engine bay and looked at every ground wire connection. I found a connection that looked pretty suspect. I believe the ground wire came to the front drivers side turn signal.

I had to remove 2 bolts and a nut to move the exap box out of the way. I removed the bolt connecting the ground wire to the body, cleaned everything, and put it back together.

I also pulled up the rear drivers side seat and checked the fuel pump connector. I unplugged it, cleaned it (even though it was already very clean) and plugged it back in and made sure it was snug on there.

I then re-calibrated the fuel gauge and took it for a drive. I drove 3 miles (about 8 minutes) and it read accurately the entire time, never plunging to E. I don't know if the issue was solved or not, time will tell, but this is by far the furthest I've been able to drive without it giving any issues. Before, it seemed I could only drive 100 feet before it would plunge to E.

But, time will tell, I'll report back in a couple days. If I were you I would first check all the ground connections especially with the rear lights since that is where you were having your issues. Hope you get yours figured out.

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Never mind, didn’t work, the fuel gauge dropped to empty 30 seconds after driving today.

Is there a way to discern whether or not it’s the sending unit? I’m at a loss otherwise.

There is a TSB regarding replacing a resistor in the instrument cluster, but Toyota stopped performing the repair in 2008, so you're on your own if you still have this issue. Apparently there is a resistor that is known to burn out in the dash, and once it does, the fuel gauge goes haywire.

I'm sure there are other things that could cause the issue, but I would imagine that the known issue would be a good starting point.

I also know this is an old post but I need help.
I just purchased a 99 SR5 and the gas gauge goes to full as soon as it is started, I can back up or just let it sit and idle and needle stays on full.
If I start going forward, most times the gauge drops instantly to empty and the fuel light flashes. Sometimes I can go a few hundred yards before it drops to E and the light flashes. If I shut it off turn the key back to on or start it the gauge instantly goes to full.
I have searched the web high and low and this is the closest post I can find to my Runners problem.
I checked tail lights and ground behind LH panel, and all is fine.

Did any of you members with this problem end up fixing yours?
Thanks JROTN

Hey man,

Try performing this instructions... (if that doesnt work, then you will probably need to swap your level sensor that is inside your tank... i would buy a used one from ebay but original toyota, the new one if you have $$$ would be better, but since you are trying to figure it out, a used one will do the trick... but try to do the steps below first.)

DO:
Vehicle has to be sitting on a level surface with an inclination of +/- 0.5 degrees.

1.With the ignition switch in the Off position, press and hold the trip speedometer reset button.
2. Continue pressing the reset button while turning the ignition switch to the On position.
3. Within 5 seconds of turning the ignition switch On, release the trip switch, press trip switch 3 times and on the 3rd press, hold the switch for 5 seconds. The buzzer will sound for 1 second at 800HZ.
4. After the buzzer stops, release the trip switch.
5.Press the trip switch one more time and hold for 5 seconds. Once more the buzzer will sound for 1 second at 800HZ.

Here's my update (and, as always, I will indicate that many people on this forum know much more than I):
I spent this past summer periodically trying to solve my issue (see my previous post on this strand). Unfortunately, the reset instructions above and the level sensor were not my issue, nor my fix. From my internet research, I concluded that there is a relatively rare but occasional occurrence wherein a single incident with the trailer plug or tail lights creates a short in the wiring that for some reason makes the fuel gauge act with the symptoms you're describing. IF you are lucky enough to find the short/fix the grounding issue, the gauge appears to go back to normal. If you can't locate it, you are out of luck. During the summer, I tried to follow wiring diagrams and systematically test every possible wiring route I could get my hands on with my meter and, when possible, checking and tightening any grounds I could get to. I went through everything I could reasonably get to and found no issues, although on a few occasions, when tightening the grounds, I definitely noticed slight changes in the patterns of "misbehavior" of the fuel gauge, making me think I was on the right track. Further, whenever I plug in my camper to the trailer hookup, the fuel gauge works again.

I never solved it, but after a summer of tons of driving and using the trip odometer to estimate refueling, I decided there was no other negative impacts to what was happening. So, when my buddy told me to my face, "Dude, its time to just let it go", I (a) pulled the dashboard (and replaced the dash lights with LEDs while I was in there) and yanked the low fuel light out; and (b) bought and installed the ScanGauge that others recommended. It creates an additional step when fueling up (i.e. inputting the amount of fuel I put in), but I don't even think about it now and actually much prefer now knowing exactly how much fuel is left, particularly on road trips.

So, if you combine all the advise above (and elsewhere) from folks who know much more than me, and my experiences, you may perhaps follow the steps of:
1. Resetting the sensors as indicated above
2. (optional) Replace the level sensor -- if you suspect it may be the culprit, or just want to eliminate it as a possibility
3. Check and potentially replace the tail light bulbs (this worked for at least one other person with the exact same issue...an old bulb was creating a short).
4. Check the grounds on the trailer wiring, tail lights, and perhaps elsewhere.
5. Give up, yank the fuel light out from the dash and install a ScanGauge.

Good luck and let us know if what works, if anything! I know several folks around the web are still searching for the solution to this rare but frustrating mystery!

Thanks Cesarel and SeaBass5000x

I tried the reset procedure tonight but did not work. When I performed the reset procedure the first buzzer sound was correct but the second one sounded like a higher frequency and did not stop buzzing until I shut the key off. I did think about spending the money for new tail light bulbs just to verify nothing was going on with them. I did try running it without any tail light bulbs at all and nothing changed.

Thanks for the help and if and when I find the GREMLIN I will post it for others.

JROTN

Good luck amigo! hopefully you will find a solution!

mine is doing this same thing and the tach is jumping too, with the key ON but not running the OD flashes, the tach and fuel gauge jump, on then off in a random interval, anyhelp would be greatly appreciated

Nate, this is what happened to me. I connected a trailer and zap! I smelled the burnt wire. I thought the smell came from behind the dashboard. I hope your location is where I have the problem. Easier to get to. I will post my results. Thanks!!!!!!!!!!!!!!!!!

Steve

I am having the exact same issue. Bought a replacement cluster with the correct mileage (expensive). Gauge worked fine until I hooked up my trailer, and no works no more.

Did you ever solve your problem?

Hopefully someone will come across this post. After replacing my starter, my fuel gauge is doing exactly what everyone here is describing. Shows full, drops to nothing with light blinking, and then back to full after restarting. Has anyone came up with anything on this? I can’t find anything anywhere.

I just recently bought a 99 Limited and the gas gauge would always show empty with the gas light blinking. Last night I added a new ground for the wire and now the gauge just reads full with no gas light. I'm not sure what to do next. Maybe I need to replace the whole gauge cluster? Please help!

I have been having this problem for years. In 2017 I posted saying that I thought that I might have had a bad tail or brake light bulb and that it was fixed. It didn't stay fixed very long. I gave up and used mileage to keep up with fuel quantity. Today I noticed that the brake light on the top of the hatchback was out. When I removed the bulb I noticed that the inside of the socket was black and burned on the inside. The socket needs to be replaced. Without the bulb installed the fuel gauge is working perfectly. I have ordered a new socket and will keep you updated as to whether it still keeps working correctly when the new socket is installed with a new bulb. Hopefully the burned socket is what is causing the short.