DBear

I've been having some odd problems lately. At freeway speeds, the transmission seems to hunt between top gear and OD at the wrong times. Going up a slight incline, it will often jump in and out of OD. (This isn't the usual problem of being right on the edge of the transition speed. In the past, it has always stayed in top gear in situations like this.) Sometimes I just have to take it out of OD to make it stop hunting. This happens primarily at light to moderate throttle. And when I'm coming down a hill at no throttle, the RPMs will drop down to idle. My hunch is that it's the TPS, but I'm not getting a CEL.

I tested the TPS for resistance. At closed throttle, I'm getting about .8 kohms, instead of the .5 which is spec. As I open the throttle, it drops to about .6, then rises fairly evenly to 1.9 at about half throttle, then drops to 1and stays there the rest of the way to full throttle. Does this sound like I need to replace it?

And my manual calss for a separate test "for continuity." Doesn't the resistance test do that?

VQrebuild96

iTrader: (1)

Unplug the tps and then see if it still does it. If it does its probably not it. Does it feel like when u smash the gas it down shifts but the car does not go any ware?

DBear

No, the acceleration feels normal. When I give it fairly light pedal at freeway speed, it downshifts and the RPMs jump up to about 3500 (which is normal for non-OD at that speed).

Can you even drive it without the TPS plugged in??

VQrebuild96

iTrader: (1)

What you are saying is normal your transmission is suppose to down shift when given throttle. If it was a bad tps you would see hesitation and engine bogging.

Yes you can drive with the tps unplug but i think it will not down shift when given gas.

DBear

No, this isn't a normal downshift when you jump on it. This is relatively light, or constant, throttle. And often it will bounce in and out of OD with little or no throttle, on relatively flat ground.

What really makes me suspicious is the fact that, when I test the resistance, it drops when I open the throttle a little, then starts to rise. It happens at just about the same throttle level as the drop out of OD happens when I'm driving.

Blassmasta

Absolutely the symptoms of a bad TPS. Think about where that thing lives most of it's life. Once you get to cruising speed the TPS does most of it's work just off idle. Think about the staticky volume control on an old radio. The TPS is the same thing. It wears in and around that spot and sends a bad signal to the computer. You've proven it with the troubleshooting you've done. I bet it's fine when you're on the gas hard. As soon as the load on the engine levels off and the TPS ends up in the just off-idle position ... the **** hits the fan.

Trini Boom

iTrader: (5)

This is a three year old thread and your response doesn't make any sense guy...

DBear

And to follow up, I did in fact replace the TPS, and it didn't help. I've been fighting with this problem for over 5 years now. When it gets bad, I just take it out of OD and it's fine. After a while I'll put OD back on, and it's usually OK for a while, then it acts up again. I think it's haunted...

99zx2

iTrader: (3)

it could be your trans (torque converter locking and unlocking), but seeing how it's still alive, i don't have a suggestion. keep us posted if you do ever fix it. good luck!

Trini Boom

iTrader: (5)

Do you have any Tranny codes? Has your O/D light been blinking anytime during the 5 years?

DBear

99--Yeah, that's always been my guess. But the fact that it hasn't gone out yet makes me think it's something else, like a sensor, or maybe the tranny solenoids. But I don't want to shell out for a new set of solenoids without a better idea that they'll fix it.

Trini--IIRC, I had a blinking OD light a few years back, but it was something like "no communication between something and something", and I made it go away somehow. FWIW, I replace the TCM (with a used from PMohr), and that didn't help.

This has become my perpetual back-burner project...

Blassmasta

It actually makes plenty of sense ... I can't help that you're not all that bright. The TPS is a variable resistor. The resistance should increase steadily throughout the range of motion. If it suddenly drops and then increases again through pedal travel guess what? The computer thinks the throttle position is something other than what it actually is and adjust fuel and spark accordingly. GUY.