strong runner one minute/struggler the next

[willmoodom]

Hows everyone? I own a 97 4runner sr5, auto, 4x4. Recently I have been experiencing some driving effects comparable to a loaded down truck or one that wont pull. I am trying to narrow it down to either a difference in gas level or wet conditions out side.
there are times I drive and the truck acts as if it's struggling to accelerate. no matter how hard I push the accelerator, it slowly increases speed reminiscent of a small underpowered car that takes for ever to upshift through the gears. Then there are times that the runner pulls like a bat out of hell. small accelerator increments bring satisfaction. shifting is on point. Has anyone experienced this before.
we bought the truck brand new in 97 and all repairs, which were minimal, were done by Toyota. Only major replacements done to the truck has been alternator and igniter unit. the latter being my fault. any suggestions.

 

[jeremy9allen]

Those symptoms are very similar to a bad TPS on these particular trucks. My brother has a 97 sr5 3.4 that just did very similar things. His ended up throwing a code for the TPS. I cannot remember the code number off hand.

 

[GottaBeTRD]

im having sort of similar plroblems i think?? what and where is the tps? (thottle position sensor?)

 

[rjyhdc4]

It is located on the throttle body.

 

[scotts97T4Rltd]

you could have a fuel pump fixing to go out. Usually a TPS will cause the throttle to hesitate, under full throttle, you should have full power regardless if it is bad or not.

 

[jeremy9allen]

The TPS could definately cause that if the resistor has a "break" or "open". I have seen them go out where you could be at wide open throttle and the car would accelerate as if you were lightly pressing the gas.

A fuel pump would cause similar symptoms, but the TPS is far more common on these trucks than a fuel pump.

 

[longeeMAC]

man this is whats wrong with my runner!

i press the gas pedal all the way down! and it seems to just accelerate faster than average... i feel no power.

so is the consensus to look at the TPS and fuel pump?

How do i fix them? is this something to leave to the professionals?

 

[jeremy9allen]

The ideal thing to do would be to get a scanner on the truck. KOEO (key on engine off) watch the TPS voltage and see if raises accordingly while pushing the gas pedal down.

Generally, they read about .5 volt at idle/closed and 4.5-5 volts at WOT (wide open throttle)

If the voltage does not raise relatively smoothly while you slowly press the peal, the TPS could be at fault. Also, make sure the voltage doesn't jump way up or down while checking this.

You can probably get a lot more info on this be googleing how to check a TPS


Good Luck

 

[inshore4runner]

if its the TPS, thats VERY simple to replace. two screws and its in and out. its on the backside of the block towards the right. if you still cant find it tomorow ill take a pic when i get home from school. i got mine from www.rockauto.com cheap and quick!

 

[IntoTheVoid]

I just replaced my TPS 2 months ago.

The symptoms I had:
The check engine light came on for awhile and then would go off. When it came on, the RPM would drop a little and the gas mileage was crappy.

Sometimes when the check engine light would come on for an hour or so and I park for 4 or 5 hours and would start my 4Runner and it would still be on, but if I turned it right back to off and then start it again, the light would go out.

Inexpensive to fix and real easy to replace.

 

[GottaBeTRD]

could one of yall post a pic of where its at cause ever since i took my TB apart my gas milage dropped and i had a check engine light a while ago. thanks!

 

[IntoTheVoid]

could one of yall post a pic of where its at cause ever since i took my TB apart my gas milage dropped and i had a check engine light a while ago. thanks!

On my 98 it is right on the back on the TB.

 

[GottaBeTRD]

thanks for that pic man! it think i know where it is on mine now. so this little guy can cause a difference in gas milage, and delayed throttle responce etc..?

 

[longeeMAC]

Do we buy new TB to replace it?

Just unplug the old one, screw out the old one, screw in the new one, and plug the harness back in????

Where do we buy the TB?

 

[IntoTheVoid]

thanks for that pic man! it think i know where it is on mine now. so this little guy can cause a difference in gas milage, and delayed throttle responce etc..?

It is a sensor so when they act up you could have a variety of symptoms.

Do we buy new TB to replace it?

Just unplug the old one, screw out the old one, screw in the new one, and plug the harness back in????

Where do we buy the TB?

You don't have to buy a new TB (throttle body) just a TPS (Throttle Position Sensors).
Unplug it and there two screws that hold the bugger in unscrew those and remove the TPS and install the new one.

I bought my TPS at NAPA auto parts here in Portland so just about any major auto part store will have them.

 

[DavidAlexander]

you could have a fuel pump fixing to go out. Usually a TPS will cause the throttle to hesitate, under full throttle, you should have full power regardless if it is bad or not.

Bingo, we have a winner. Sounds like your fuel pump is going out. It would be worth it to change the fuel filter first, that might be clogged as well.