M1STAHCH33KS

I've been having a problem lately with my 2000 TL and I think that it is my transmission. When I am in park or neutral and my foot is off the gas, the engine continuously revs from 0-2000 RPM's. Then if I put it in drive, still with my foot off the gas, the car will drive and climb to about 25-30 mph. This has probably been happening for about 2 weeks now.

My check engine light finally came on this morning, and when I checked the code, it read "P1768 A/T Concerns."

Does anyone have any idea or experience with what this problem could be, and if so, any ideas/cost to fix it?

Thanks!

Karanx7

iTrader: (2)

Wow... That's...

Do you just drive with the brake pedal?

I'd get that checked out professionally. Is the throttle cable loose? Check the throttle body to see if the thing is stuck.

Skirmich

Wierd the ECU Code is Something from the Torque Converter Solenoid Isnt?
The Wierd thing is that I Dunno why it has Anything to do with a Reeving Engine!!

Karanx7

iTrader: (2)

All I can think of is a stuck throttle.

When you press the gas pedal, is there a resistance in the beginning? Or does the resistance only happen about halfway pressing the peddle?

Skirmich

Yeah I Concur, Thankfuly we dont have silly DBW so a Stuck Butterfly or Gas Cable is most likely.

Perhaps the Spring on the TB is weaker or something pike that..

01tl4tl

Torque Convertor,,read how it works on wiki and you will understand the surging and codes

inspect trans dipstick- fluid color and smell???

fsttyms1

FIrst thing i would look at is is the IACV, if the car is surging in idle like that. Take it off and clean it, clear the codes and see what happens.

M1STAHCH33KS

I didn't notice any resistance on the pedal, though when I decelerate the car sometimes feels like it is pulling, as if it were on cruise control or something. I cleared the code to see if it comes on again, but in the meantime I will check all of your suggestions (which were awesome) and post what I find.

BAGII

I've heard about this problem being caused by a faulty ECT engine coolant temperature sensor. The PCM sees the ECT sensor reading and IAC valve tries to adjust idle speed.

kalick

i am having this same issue any help guys

01tl4tl

do the visual of throttle cables at TB - lube springs
clean IACV on bottem of TB
clean throttle air plate
see other suggestions above

describe your symptoms in more detail, recent maitenance, car is new to you? miles on it etc.

jlee133541

My guess is faulty or stuck IAC. Unplug it and see what the result is. When it's in park 0-2000 is the range you typically see when the IAC fails. If you have a scan tool you could look at coolant Temp. If the temp being reported is way out of whack with what the gauge on the dash is reading or if the thermostat cycles irregularly or sticks that may require a second look. I don't know what the success rate is for cleaning IAC valves is. If you pull the throttle body you may want to have a fresh gasket the first time you remove it. You can usually remove it a couple times with a fresh gasket without a problem. My vote is for a bad IAC. I would replace it if I could afford it. Try and clean it if I was strapped for cash.

MilwaukeeDave

iTrader: (3)

Awesome. I'd name it KITT and see if it takes directions.

broly

some of you guys are so smart that i wonder how mitt is so dumb.

your theory is nearly correct, but it's not the ECT--it's the IAT (intake air temperature sensor that's on the intake manifold).

specifically, the PGM def uses the IAT input to determine the throttle stuff and a faulty one can definitely result in some "self driving" in drive.

for me, on reasonably hot days (\geq 25C) the car would occasionally accelerate in the lower-band (no higher than 2.5k rpm) all the way up to the highest gear possible (usually 5, around 80k) slowly.

for me, what fixed the issue was:

1. replacing throttle body (older TB had a new IACV and still had issues. TPS was doneskis)
2. checking for vacuum leaks (this includes the resonator. the bottom of mine was *cracked*).
3. replacing the IAT

after all of the above (no small task, tbh), the tach needle sits just a smidge below the second graduation below 1k rpm (2/3).

some post mortem on this issue which has nagged me since i hit the curb over 8 years ago:
the IAT is a pretty important sensor.

from what i gather it uses the ideal gas law (holler robbie boyle and johnny dalton) to determine volume/pressure etc, so a faulty one could definitely throw a wrench in operation.

makes me wonder how many people experiencing this issue without even thinking about a missing resonator.

• the resonator has a 'U' shape tube that clearly cools the air before it's fed to the air filter/box area.
  • i understand, yes, that the resonator 'silences'. but it also is responsible for completing the 'air circuit':
  • 

also, just to rebut any potential "dude it's just the resonator it doesn't do anything but silence the sound", i point you to the following diagram which clearly considers the resonator as a part of the vacuum system:


makes me wonder how many people had more time than either money or sense, and took the opportunity (in these easy-credit times) to 'look smart' and do something stupid (that doesn't look stupid until years later.

• i doubt the resonator removal becomes an issue until later in the car's life).

fwiw i don't notice much of a difference in sound when i had a broken resonator, compared to my working one

Karanx7

iTrader: (2)

^ Not sure why you're rezzing an old thread, but you're post has a lot of misinformation. The resonator IS just a silencer. Removing it does NOT affect the car's vacuum system, nor does it change the metered air intake. Any kind of problem of "self revving" is entirely caused by a vacuum leak. This is usually the IACV in our cars.

Also, your IAT theory is wrong. It won't cause that level of surge. As maybe the only one on this forum that has actually tuned a 2G, I can show you all of the maps that use IAT. It is certainly used for idle target values, but it won't be enough to cause that kind of surge. You need a straight up vacuum leak for that.

You're stupid as shit if that's all you can think of. The problem was obviously the IACV.