acceleration problem?

[Badlands]

2002 TOYOTA 4Runner V6

PROBLEM: Intermittent problem with acceleration? Only happens when sitting at a light or ideling for a couple of seconds. Then when I go to hit the gas, there is a hesitation before it accelerated (advances slowly then all of a sudden it seems like it gets gas and accelerates?)

Fuel pump problem?...throttle body sticking...gas pedal? It seems like it is a gas related issue...seems like it doesn't get gas for a second or 2 and then it kicks in??

Any ideas or suggestion would be greatly appreciated.
-B

[Bighead]

The one time I had that problem it ended up being bad gas.

[04 Rocko Taco]

The one time I had that problem it ended up being bad gas.


Exactly my experience also.

[MTL_4runner]

The one time I had that problem it ended up being bad gas.


That's probably what it is. The 2002's are throttle-by-wire so you could check to see if the throttle plate is sticking but it's not very likely. The timing will retard like crazy when you step on the gas and the knock sensors kick in. Drive it down to less than 1/3 tank and then add name brand high-test and see if your condition still exists.

[Badlands]

will run the tank down to almost empty and refill with super...but it has been doing it for quite sometime but only now and then...now it is starting to get worse and on a daily basis.

I'll give the gas thing a try though....thanks!

[Cebby]

How many miles on the engine?

[Badlands]

79,000 miles

[MTL_4runner]

It could be coil pack, TPS, FPR or any host of other items, but it's best to begin eliminating things one at a time and making sure you have a good tank of gas to start with is key to getting a good diagnosis.

[Badlands]

okay...problem still there!! grrr...

So this is what i have done so far:

-emptied the tank to under 1/4 and filled up with "super" (expensive) gas 3 times so far
-had it in for servicing (mentioned the problem) they cleaned throttle body and MAF

It still hesitates (at times)...what i have noticed is it tends to do it more when i am waiting at a corner-full stop-wheels turned (right more)- transmission in drive- foot on brakes...

let go of brakes...creeps forward (normal)...press gas pedal, still creeps as if not getting gas(not normal)...press harder on the pedal (hesitates for a second or 2) and then it kicks in and drives normal?

and it does it only once and a while?

any more ideas out there?...any help again would be greatly appreciated.

-B

[surf4runner]

sounds like it could be vaccuum related???

anything changed recently that may still be loose?

[Badlands]

No...nothing changed.

It has been doing it for quite some time now (before service...and like i said intermittently)

and it definately feels fuel related? i release the brake pedal and it creeps forward (like normal) and when it does kick in there is no clunk from the trannie (so i rule out transmission slip)...it just seems to all of a sudden get fuel? (at least thats what it feels like)

and the wierd thing is..it tends to do it when i am stopped for a bit and I have the wheels turned to the right?

really freakin' wierd and frustrating (cause I'm usually trying to merge into traffic and it wont go!)

-B

[slosurfer]

Could it be fuel filter related? Maybe it is only clogged enough to cause a problem at idle or slight pressure.

[Badlands]

the mechanic says fuel filters usually don't need replacing? (thats why he only cleaned the throttle body and MAF)...but I'm leaning towards replacing that next?

-B

[YotaFun]

Replace it.
It will go, Toyota can have my family jewels if they can prove to me that a Toyota fuel filter does not need to be replaced.
They sell the replacement, so why wouldn't it need replacing?

[Seanz0rz]

the mechanic says fuel filters usually don't need replacing? (thats why he only cleaned the throttle body and MAF)...but I'm leaning towards replacing that next?

-B



the filter does exactly that, filters particulate matter out of gas, just like an oil filter. of COURSE it needs changing occasionally!!!! IIRC, it wsa 34 ish from the stealer, order from northridge toyota, links on here. they got a sweet discount.

its likely its never been done, so even if it does not fix your problem, it should probably be changed anyway.

[Badlands]

Thanks guys...I will replace the fuel filter next week and keep you posted.

Hopefully it will be something that simple.

-B

[MTL_4runner]

1) Is the vehicle stalling at the lights too?
It might be worth having a look at the fuel pressure too.

2) Also did you have any maintenance done prior to this happening (like T-belt, WP, etc)?

3) When the engine does start climbing in RPMs is it rough or does it climb smoothly?

[Badlands]

Hey MTL

1) it runs perfectly (idle, acceleration) there is no stalling or rough idleing.

2) had the T-belt, water pump and all the major hoses done in the spring

3) runs smoothly...I'm telling you...it purrs like a kitten and when it gets gas, there's absolutely no stuttering or bucking...nothing, nada, zippo

it's a split second thing...where it doesn't seem to get fuel when i first apply pressure on the gas...then i give it more gas and a split second later its normal and gets gas...and then its smooth sailing after that. and like i said it does it ever so intermittently (and i noticed more when I am immobile for around 30 sec. and the wheels are turned to the right...as if to merge into traffic...let go of the brakes and it creeps like it should...but then when i put my foot on the gas...it still creeps....so i apply harder and a split second later...it moves....and it moves the way it should...no stuttering or nothing.

[MTL_4runner]

Thanks fot the info and it makes me think.....
Are your brakes sticking at all?

[Badlands]

nope...just replace the front disc and pads...and the backs were adjusted during servicing.

-B

[BruceTS]

OK a longshot... because its throttle-by-wire, several other factors can cause the problem....
I haven't looked at exactly how it's set-up, but if it's like the 1GR-FE engine, the throttle pedal assy could be the problem or the throttle body.

[MTL_4runner]

OK a longshot... because its throttle-by-wire, several other factors can cause the problem....
I haven't looked at exactly how it's set-up, but if it's like the 1GR-FE engine, the throttle pedal assy could be the problem or the throttle body.


I don't have as much experience with the throttle-by-wire systems either so it would be natural to suspect those since when you step on the gas you really aren't moving the throttle directly anymore. I attached an example of each so people can reference the two types (1GR vs 02+ 5VZ) together. They are very similar in operation, but certainly not interchangeable by any means (one of the big differences being there is no IAC valve on the 1GR throttle body).

[MTL_4runner]

My thought was that it could be the TPS or the throttle motor itself causing the issue but you'd need to test it to find out. I attached the FSM testing for your throttle body so you can see if you find anything out of the ordinary which might be causing your issue.

[Badlands]

thanks MTL...I'll give it a try. + replace the fuel filter.

I'll post back results.

-B

[MTL_4runner]

thanks MTL...I'll give it a try. + replace the fuel filter.

I'll post back results.

-B


No prob and I asked another guy who has a bit more experience this throttle-by-wire system than I have to chime in. Hopefully he'll keep us all going in the right direction until you get your issue solved. In any case give those tests a try and see how you make out.

[toytech76]

I'm probably a bit late to this thread but I was just now able to get access. New to the board so here goes. I'm willing to bet your problem is with the fly by wire throttle. One of my customers had the same problem with his 03 taco. He went to nail it through an intersection and it just fell on its face. I went on a T/D with him to confirm and had the same thing happen. I replaced his throttle body and the problem was fixed. You can order the throttle motor sensor by itself or just get a used tbody. If you do want to fix instead of replace the tbody, its probably a good idea to replace the throttle motor sensor and the tps all at once. Hope this helps