My Throttle Position Sensor TPS failed in the middle of a 5k mile road trip

[JohnOfTheJungle]

This is a quick success post, maybe will help someone in the future.

I am at the start of a month long road trip from NY -> TX -> CO -> MT -> WY -> NY in my 220k mile 97’.

Pulling into Nashville last night literally the last 5 miles out of 800 miles driving and I noticed the 4Runner jumping out of gear on the highway, as well as when coasting on a side road at 30-40. I immediately feared the worst - that my transmission was about to bite the dust.

I parked it for the night and started this morning for another 700 miles. Almost from the get-go things went south - the runner bucking all over the place, unable to hold a gear, torque converter coming unlocked.

Here’s a video, notice the RPM while trying to cruise at 60. I drove like this for about 150 miles.

3rd gen 4runner TPS malfunction - YouTube

I deduced it was not the trans however because it stalled while in neutral. It also didn’t seem to be slipping, I could also usually take off fine from a stop even under hard accel.

I changed all the spark plugs at a truck stop Dennys parking lot. The old plugs have 40k on them and looked perfect. Didn’t fix it. Ran fuel injector cleaner, nope. Put some trans fix in the trans, didn’t fix it. I’d read about the Throttle Position Sensor (TPS) but didn’t know much about it.

I had my wife call a few Toyota dealerships while on the highway towards Little Rock. None of them had one. I stopped at an Autozone on a whim because I wanted to try running some sea foam through, thinking maybe I’d gotten some bad gas.

Luckily they had an AC Delco brand TPS in stock for $80. Swapped it out in the parking lot in 15 minutes. Worked perfect and fixed the problem. Been choochin along today for 500 miles so far.


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[brillo_76]

You didn't have the cel light on when it was acting up?

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[JohnOfTheJungle]

No CEL and no codes, I scanned a bunch of times with my OBD scanner. That was also frustrating because I had zero diagnostics to go from.

The TPS was literally throwing money at the problem, but when you’re in the middle of a road trip time is money, and I got lucky.


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[Sarki]

Glad to hear you were able to resolve it fairly quickly.
Having issues during a road trip is a drag.
Best of luck for the remainder of your trip……motor on safely into the New Year!

 

[Devbot]

Ahhh, that brings back memories, my TPS died in my old Dakota and I had the same train of thought as you did thinking it was my trans. I tried putting up with it for about a week, but it gets pretty damn embarrassing when you have a couple chicks in the cab wondering what POS they got inside of :doh: Joe Diffie never mentioned that part I guess ound:

 

[brillo_76]

Wow. I haven't seen that. When my tps went it threw my CEL and recorded the sensor as bad.

Hope the rest of your trip is smooth and uneventful.


Thanks for reporting. This may definitely help someone.

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[Bad Luck]

Wow. I haven't seen that. When my tps went it threw my CEL and recorded the sensor as bad.

Hope the rest of your trip is smooth and uneventful.


Thanks for reporting. This may definitely help someone.

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When the TPS started to go bad on my old 4Runner there was a dead spot between 22-24 percent throttle where the sensor would drop to 10 percent like it thought I let off the throttle. Caused some super harsh and jarring shifts and torque converter locking/unlocking. Luckily I could watch the throttle position with my UltraGauge and figured out what it was. Never set a CEL the couple days that I drove it around waiting on parts.

 

[19963.4lsr5]

When the TPS started to go bad on my old 4Runner there was a dead spot between 22-24 percent throttle where the sensor would drop to 10 percent like it thought I let off the throttle. Caused some super harsh and jarring shifts and torque converter locking/unlocking. Luckily I could watch the throttle position with my UltraGauge and figured out what it was. Never set a CEL the couple days that I drove it around waiting on parts.

I have a spot between 15 and 20% that the LTFT jumps up. I have two spare sensors to see if it goes away.


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[JohnOfTheJungle]

Thanks for the well wishes. Hopefully the rest of the adventure is smooth, if not I’ll be sure to let you guys know of any mishaps.


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[desertegal7]

when mine acted up i disconnected it while engine is warm and running a couple of times until rpm back to normal.
eventually now is normal thus im suspecting dirty IAC valve.

 

[3bears]

when mine acted up it just had a dead spot. I was throwing no codes. Having had this issue on a volvo that a tps fixed, I installed a new tps on my 4runner, and it fixed the dead spot.

 

[JohnOfTheJungle]

when mine acted up i disconnected it while engine is warm and running a couple of times until rpm back to normal.
eventually now is normal thus im suspecting dirty IAC valve.

Was it acting up while driving or just at idle? Can you drive without it connected? I didn’t check my IAC at all


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[desertegal7]

when i cold start it idles araound 1700, when warm it drops to 1200-1300, and thats bad when braking.
it was steady but high idle, turn on/off and it stay araound 1100, drive then stop its 1200ish, but was steadily faulty no fluctuating, not acting up while driving but can notice hesitation when crusing (mine is manual transmission)

tps, iac, mass air flow, ecu.. etc are all depend on each other, when one is acting up the other comensates that what makes the acting up i guess.
clean mass air flow as well
also check your collant temp sensor for firm connector locked, if it plays araound then provides incorrect reading making tps and iac acting up.

also im assuming no vaccum leak somewhere.

im no mechanic just a diy-er

 

[Endlessblockades]

Mine threw a code before I noticed anything was wrong, but I just wanted to add that it's nice to have a stubby JIS screwdriver on hand.

 

[JohnOfTheJungle]

Mine threw a code before I noticed anything was wrong, but I just wanted to add that it's nice to have a stubby JIS screwdriver on hand.

Yea the bottom screw on mine was stripped so I had to take the throttle body off to get it out. Otherwise a stubby JIS would have been perfect (which I don’t have and need to add to the toolbox)


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[JohnOfTheJungle]

The Runner has been solid over the several thousand miles we’ve put on it since last week. After I replaced the TPS we spent a few days in Texas driving back and forth from Dallas to Austin and around DFW. Then drove another 15 hrs from Dallas to the highest city in the US - Leadville, CO.

Today we took it over Loveland Pass (the continental divide) on the way from A-Basin to Denver. Ring in the New Year in Denver then tomorrow we ride out 11 hrs to Big Sky, Montana.

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[nissanh]

I replaced the TPS even before it gave me any issues. Good Stuff! I have not taken my 97 also closer to 220K miles on highway since 2016 (year I bought the Cruiser). I've been thinking of taking it for a drive but no catalyst to do so... After reading yours, I might do so very soon. Enjoy trips whenever you can. I did a road trip in the Cruiser to Tuscaloosa AL last Monday... 2000 miles in 3 days.

What is the part number of Tokico shock you have in the rear? Do you remember it's fully compressed and extended lengths?

 

[JohnOfTheJungle]

I replaced the TPS even before it gave me any issues. Good Stuff! I have not taken my 97 also closer to 220K miles on highway since 2016 (year I bought the Cruiser). I've been thinking of taking it for a drive but no catalyst to do so... After reading yours, I might do so very soon. Enjoy trips whenever you can. I did a road trip in the Cruiser to Tuscaloosa AL last Monday... 2000 miles in 3 days.

What is the part number of Tokico shock you have in the rear? Do you remember it's fully compressed and extended lengths?

Re: shocks - it’s the tokico black for the LC. I searched my email and can’t find the order confirmation so I don’t know the part number offhand. I previously had 5100’s for a Tundra but they were too weak and couldn’t damp the suspension enough. I think the Tokico’s do a better job, they’re physically beefier, and cheaper too.

Re: the trip - been a dream of mine for a bunch of years. Every trip I’d take out west I’d see all of these sick Toyotas and wish I could have mine out. Now I finally do for the next 2 weeks and it’s the best.


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[JoeT4R]

P/N should be 48531-69417. I have the same ones pending installation to replace my 5100's.

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[theriddler]

Re: shocks - it’s the tokico black for the LC. I searched my email and can’t find the order confirmation so I don’t know the part number offhand. I previously had 5100’s for a Tundra but they were too weak and couldn’t damp the suspension enough. I think the Tokico’s do a better job, they’re physically beefier, and cheaper too.

Re: the trip - been a dream of mine for a bunch of years. Every trip I’d take out west I’d see all of these sick Toyotas and wish I could have mine out. Now I finally do for the next 2 weeks and it’s the best.


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I had the exact same Bilsteins in the back and replaced them with the LC shocks and I could not be happier...and yes they're a heck of a lot cheaper! I can't enough good things about them, it's almost as if they were tuned to run on 4runners. Can't say I'm a fan of the Bilstein 5100s, I do have the 6112s in the front of mine right now and I am pretty happy with those.

I had the TPS issue you had as well on a '99 4runner we had for a while. I took it to the car wash and it didn't want to shift afterwards. It wouldn't shift until 4-5k rpms and it wasn't throwing a check engine light either. Luckily I found the issue fairly quickly and it was inexpensive.