DblCabMN

Hi guys,

Long time lurker, had to join up because i couldn't find anything out there already on my problem. Really hoping for some ideas on where to go next.

Vehicle: 2003 Tacoma Double Cab V6/5VZ-FE Auto
Mileage: ~99,300
Air filter replaced by me when i bought it. Also had an oil change at that time. All fluids under the hood at the correct level.

Bought at ~97,000 miles, not sure if 90k service was completed, though serp. belts and ATF fluid look good. CEL has been on since 100mi after purchase(awesome, i know), had a friend read it and it's 1st O2 and CAT codes. Cleared, and came back after another 100 or so, left it on since then. New codes may be appearing, but i haven't had a chance to re-scan.

On my way home tonight while cruising around 65mph, out of no where i lose throttle response and the truck gets oddly quiet. My tach hasn't worked since i bought the truck about 2k miles ago. So, thinking the engine stalled i shifted to N and turned the key off, then started it again. I hear the engine turn over, start and run quietly - Still no RPM response until the pedal is nearly to the floor. Once the pedal travels about 2/3rds of it's full motion, i get weak power. I pull over and pop the hood with the engine running. When i manually move the throttle with my hand, nothing happens until i get what feels like 1/2 way through it's motion and i feel something move internally.

So i go and turn the key off and let it sit for a minute, Fire it up again, same symptoms, turn key off, count to 10, turn on and everything's back to normal.

I gently drive it home and thinking it might be the MAF i pull it and notice the intake side (?) is very grimy on the temp sensor and the other two smaller units in the shaft look 'OK' but not great. A good hose down with CNC BrakKleen and after drying, things look great, reinstall.

I also had a bottle of SeaFoam on hand. So i removed the PCV hose and followed the instructions sucking a little in at a time over the course of about a minute keeping the engine alive with the throttle (a TON of smoke/steam/whatever it is came out during this process alone), finishing with a 'big gulp' and letting it die. Did about 1/2 bottle total. Let that soak for a good 15 minutes. Put everything back together. Went to fire it up, took three - three second attempts at starting to fire up, more smoke, had to tap the throttle a few times to keep it alive.

Went for a 10 mile ride to burn it off, doing heavy footed starts/accel's until exhaust was 'clean.' Acceleration was much smoother, more powerful then before cleaning. Got a good 5 strong pulls in. But then, on one of my 0-50 pedal to the floor accelerations, the above problem came back. No throttle response when pressing the gas pedal until it's nearly to the floor, then any power given is very weak.

This time i tried something different. Put it in N, turned engine off, On (but didn't start it) three times, then fully turned the key to start, fired right up and pedal response was back to normal.

Truck ran fine for a few more minutes then the problem re-appeared... repeated above steps, normal function was back... rinse and repeat...

Truck is now sitting in my garage.

I'm thinking i'll need to pull the TB and take a look around tomorrow, too cold/late tonight for me to get into it. Any ideas would be greatly appreciated!

sidewinder

check out throttle position sensor, not peddal position, throttle position, good luck!

DblCabMN

Thanks for the reply,

So when i manually move the throttle under the hood, and i get no response it could be the TPS? That makes sense, thanks!
i found this article.
http://www.buzzle.com/articles/sympt...on-sensor.html

Doing a bit more searching into fuel filter/fuel pump symptoms i was thinking maybe it would be one of those... but i don't have any stumbling or all out stalling...

I think what i'll do is pick up a new TPS, Fuel Filter, and for the hell of it, PCV valve(was pretty gnarly when i had it out.)

Give the install a shot tmrw after work and hope for the best.

ZUK

iTrader: (1)

What you describe sounds like simple linkage. The butterfly opens up as more throttle is given. Gotta be something simple right near the throttle body where the throttle cable pulls on the lever near the body.....

jonnydclark

Hey there.
I know nothing about your 4-runner but what you describe is the identical symptoms to my GS300 last year. It is called limp mode and is due to the traction control system and drive by wire. Basically you have a pedal sensor, a motor to turn the butterfly valve to the desired position and then a throttle position sensor to verify the motor is functioning correctly. If for some reason the computer thinks there is a problem with the system it goes into limp mode. Toyota, being the company we love, decided not to leave us stranded mid freeway. Therefore, instead of putting the pedal sensor under the dash they have a cable and put the pedal sensor in between the cable and butterfly valve. So when you push the pedal the cable pulls on the sensor but doesn't actually move the valve until the last 1/3 or less of the pedal movement. The ideas is you can floor it and at least get to a shop or home. Theoretically you could ohm out the TPS and the pedal position sensor and see if there are any dead spots but I found it not so clear. By the time I was done both sensors and the motor were replaced. Turned out the motor fixed it but it cost the most so I didn't buy it until after trying the other two. It makes the wife real happy when you put a part on and say ok honey I think its fixed. Then she gets 10 minutes away and it goes into limp mode.

Also, in my case the TCS and ABS lights would turn on in limp mode.

Hope this helps. PM me if you have questions.
Jon

DblCabMN

Nabbed the TPS this morning, go to throw it on...

Stripped screw...

Oh yeah.

Gotta limp this thing to work, picking up a extractor this evening and will hopefully be able to pop it out tonight.

I had read somewhere else that the 'cleaning' method for this type of sensor is to move it fully open/fully closed 100 times. As it was still not working correctly this morning, with the engine off/key out i pumped the gas pedal from stop to stop 100 times, started the engine, so far put about 20 miles on it this am tracking down the TPS part and the problem hasn't reappeared yet.

My round trip to work and home is about 30 Miles, i'll check back in tonight after I swap the TPS and let you know if the 100 cycles worked as a good temp cleaning. And how much of a PITA removing the lower stripped screw on the TPS is. I might just pull the whole TB for a cleaning anyway so i'll have better access...

jonnydclark

Yea, I actually had to use my impact screwdriver (hand held swing hammer style) to get one of my screws out.

DblCabMN

Yeah jonny, i've used my Makita 18v impact driver to get stubborn screws out on my 70's Honda motorcycles, works hella good! I just 'hug' the frame and brace the back of the driver in my shoulder so it doesn't pop out and strip.

I was just in a crunch to fix it before going to work this morning, so i cut corners (not pulling the whole TB out and working on it on the bench) and just used a short phillips and paid the price!

DblCabMN

No time last night or tonight to pull the TB. Things came up, but the good news is the '100 pump' trick seems to have had a good effect. The problem hasn't reappeared in about 50 miles! (was happening within every 5 miles previously) However i will still be swapping TPS/FF out Saturday morning.

DblCabMN

Alright.

So, bad news is NAPA has the wrong part # in their books for the TPS Sensor.
Good news is, i don't think i need it at this time. Looking closer to my 5VZ-FE throttle body, i noticed A) It was dirty, so i cleaned it (and the 5-6 holes in the top...) B) the TPS sensor is 4-pin, not 3 like the part listed @NAPA for the v6 5VZ.

I think i may have inadvertently adjusted it 'close enough' for it to work normally, i'm over 100 miles now with no issues since i loosened the top screw, maybe bumped it a hair?, then did the 100 pump trick... That's all i got.

Only facts i have on the 100 pump working:
Read about the fix (100 motions of the sensor) for the type of electronic part it is somewhere on the internet.
Truck the morning after loosening the screw, and later re-tightening, had the 'limp mode' problem. = No throttle response.
Key out of the ign. 100-pumps, no reappearance of problem in over 100 miles. I will update this thread if i ever have to actually replace the TPS.

This thread seems to explain my problem though it's about 01/02's
https://www.yotatech.com/forums/f180...or-tps-133112/

Also, and most importantly, the 2003 TOYOTA TPS is adjustable...


4-Pin


And on a side note... this is how far open the butterfly valve gets when the throttle is fully 'open' (when it's at the stop) - First 'third' of travel doesn't move the valve... Don't know much about fuel injected engines, i'm used to Carb's, so i'm guessing this is sort of a 'pilot' circuit until the next third when the valve opens and so on through the motion of the valve.




Also, changing the fuel filter... bad idea. So. Much. Gas. Everywhere...

t4r4life

maybe loose cable maybe bad tbp sensor