Power loss

[toybox]

At lunch today while I was driving back up a small hill the gas pedal stopped giving the same feedback. When I got to the top of the hill and all the rest of the way back to work I was gunning it and next to nothing was happening. Having the V8, when I step on the pedal it usually drops down a gear and sets me back in my seat a bit, but now it is like something is limiting it. The engine revs higher when i step on it but with no corresponding power to the wheels.

I checked that it was in "D" and that no dummy lights were on. To tell you the truth it sounds like the tranny but I just don't want to think that. Any ideas????

I'm almost afraid to drive it home, that is how bad the pickup is right now. I'm worried!

 

[sharp4runr]

Hmm, that is scary. Sounds like a clutch problem. Reminds me of when my clutch went out on my 5speed celica. I would step on the gas while the car was in gear but no power output, just plenty of revs. I'm not sure if a manual and an automatic work the same way though.

Is it the same after the car cooled down?

 

[toybox]

Is it the same after the car cooled down?

Don't know yet. When I leave work if it still happens it is going straight to the dealer and I will have someone pick me up tonight.

The weird thing is that tranny problems are usually progressive and this literally happened in an instant.

 

[sharp4runr]

You might want to have it towed to the dealership if it's giving you that much problem. It would suck if you got stuck on the side of the road getting to the dealership too. The dealership should reimburse you the money if the repairs are under warranty.

If it's fine after work, I'd still take it to the dealership to have them check it out.

Good luck with it and let us know the outcome.

 

[CMiYC]

The weird thing is that tranny problems are usually progressive and this literally happened in an instant.

You sure about that? With as complex as automatic tranmissions are (especially these days), all of a sudden problems are a norm. The issue you have sounds like the tranny. If the engine revs and you don't go anywhere, that doesn't leave many options... Although it could be a problem with the differential or a few other things. It may be as simple as the ECU isn't shifting gears. Could be as bad one of the clutch plates got burned up and the tranny can't shift.

Hopefully its not too late... but you should take the towing suggestion. If it is the tranny, no sense making it worse.

 

[rando]

The weird thing is that tranny problems are usually progressive and this literally happened in an instant.

I had two trannies go out on an 2002 explorer. They both went nearly instantly. The car worked fine when I parked it. When I got back in, it started slipping and within a few miles would hardly move at all. On the first tranny, the failure caused the check engine light to come on. The second time, there were no lights, bells, or other indicators ... just high reving and the car rolling backwards on hills ... that kind of thing.

With these hi-tech trannies, there are MANY failure modes. The good news is that most everthing has a sensor such that your ECU will spit out a diagnostic code and tell the techs exactly which parts have failed. Of course the factory dictates the repair procedures and thus a thorough (root cause) analysis may not get done. I suspect in the case of my Exploder, that's why I ended up with a 2nd tranny failure only a few hundred miles later. It's likely that some other component was causing the tranny to fail (ECU etc). It's just a theory of mine.

Good luck!

 

[toybox]

It is completely back to normal now????? I wasn't dreaming it either as I had to drive several miles with it acting like that. Do you think it could have had anything to do with the VSC because that is what it felt like....giving it gas but the VSC limiting the power to the wheels?


I don't know if I should bring it in now or wait for inspection in a month. It is not the most convenient thing to bring it to the dealer.

 

[sharp4runr]

Glad to hear the truck is back to normal, though a little disconcerning at the same time. It couldn't hurt to take it in just for them to give it a once over. Those were very wierd symptoms...

 

[rando]

You might bring it in just to let them check if it produced any error codes. If not, you may have just exercised a design 'feature'.

 

[toybox]

I wish I had one of those scanners so I could do it myself. It is such a PIA to bring it to the dealer.

I will get it checked out though probably on the first of August when I can get the truck inspected.

 

[ericr]

Re: Power Loss

I've got an '03 V8 limited and I too have experienced an intermittent power loss problem. It's an annoying problem. For mine it happens when it's warm outside; usually well over 80 degrees. It more commonly happens when the AC is on and when I'm using more power (going highway speeds and/or up big hills). Sometimes while driving fast in the mountains when it's hot and displaying this behavior, I also notice a large drop in gas mileage. The power loss is substantial when it happens. It feels really underpowered.

The engine sounds different when it's in the power loss mode. It sounds like what I at first thought was a transmission problem. Kind of a louder, deep, throaty groan.

The dealership claims that everything's fine.

My theory is that the viscous fan clutch is locking up and robbing power from the engine. The viscous fan clutch is at the center of the engine fan. The way it works is that when it's cool, the fan "free-wheels" thus spinning at alot lower speed than the crankshaft. As it gets hotter it begins to lock-up, making the fan turn at a higher speed that is closer to the crankshaft speed. Normally the added air flow caused by the fan going faster would cool down the radiator more, lowering the temperature and causing the viscous clutch to release and lower the fan speed.

My theory is that its locking up and staying more locked up than it should.

The control for the viscous clutch is purely mechanical and therefore, does not tie in at all with any of the vehicle diagnostics. On GM vehicles they've gone to an electronically controlled viscous clutch but Toyota's are all mechanical. So if this is the problem, that would explain why nothing would show up through the OBD2 diagnostics.

I just got my own OBD 2 scanner system that works with a laptop and I'll be doing some experimenting on the problem. Even though the diagnostics wouldn't report an error code, there are a few things I can do with the scanner system I've got. I can monitor the engine temperature and correlate that to the power loss behavior.

I can also log the 0-60 performance of the vehicle in both the case of the power loss situation and when it's working normally. I can then at least have some concrete data to show the dealership.

My biggest problem is convincing the dealer there's an issue, independent of what the actual cause is.

-Eric

 

[c44me]

toybox,

I have had the same thing happen six times in my '03 V8. The first time, I pulled out onto a busy street to find I was barely moving - it took about 5 seconds to reach 20 MPH, and fortunately I was not rear-ended. Depressing the throttle pedal spun up the engine, to about 5000 RPM, but didn't produce more acceleration. I drove a couple of miles like this, checking all the lights and control settings, which were all normal. Finally, I pulled over, shut down the vehicle, waited five seconds, and started it back up - it worked normally until the next time this happened. Working with Windows computers a lot, my first thought when having a software problem is to power-cycle.

Once, this happened a quarter mile from the dealer. I took it in, left it running in the lot, and a tech came out to drive it. He drove it a few blocks, and said, "This is reallly screwed up", but unfortunately he power-cycled the vehicle before hooking it up to the analyzer. He believes it is an engine control computer problem. I agree. Based on how all the other control systems work in the 4Runner, I think the engine control software is as buggy as a June evening in Ohio. The dealer said they do not expect any updates to the control software.

Funny, you pay $100 for an MP3 player and the manufacturer provides firmware updates every couple of months until it works like a charm. Pay Toyota $32,000 for a 4Runner, and they make no effort to correct software problems, or even recognize them.

So, when it happens next, just pull off the road, shut the vechicle down, count to five or ten, and restart.

 

[c44me]

Yes, alpha, I agree the problem with this problem is that it's not a big enough problem . I've scanned newsgroups for a year and a half now, looking for this issue, and toybox seems to be the only other case I've found that appears to be the same problem. So this particular problem would not be a big pressure on Toyota to release a software fix.

But surely many people have by now noticed that the Downhill Assist Control does not control your speed, the Hill Start Assist does not stop you from rolling back, and the VSC does not stop you from skidding, or when it does kick in, it is usually an inappropriate response. These problems are inexcusable and easily recognized, and THEY CAN KILL YOU. The 4Runner needs a complete re-working of its control systems.

 

[toybox]

THEY CAN KILL YOU.

I must say it was pretty scary pulling out into traffic when this happened so I agree this could cause a bad accident.

And c44me, you described the problem exactly! I got to work and shut it off for an hour and then it worked perfectly normal again. The way it felt I knew it was a computer controlled thing and after it went back to normal I knew that Toyota wouldn't be able to find anything. So now I just hope it doesn't happen again.

 

[alpha]

huh, weird.. i think i accidentally deleted my above post.. i was deleting a post on another forum last night, and i think i deleted this one too.. oops..

 

[ALLfor4]

Power Loss

toybox,

I have had the same thing happen six times in my '03 V8. The first time, I pulled out onto a busy street to find I was barely moving - it took about 5 seconds to reach 20 MPH, and fortunately I was not rear-ended. Depressing the throttle pedal spun up the engine, to about 5000 RPM, but didn't produce more acceleration. I drove a couple of miles like this, checking all the lights and control settings, which were all normal. Finally, I pulled over, shut down the vehicle, waited five seconds, and started it back up - it worked normally until the next time this happened. Working with Windows computers a lot, my first thought when having a software problem is to power-cycle.

Once, this happened a quarter mile from the dealer. I took it in, left it running in the lot, and a tech came out to drive it. He drove it a few blocks, and said, "This is reallly screwed up", but unfortunately he power-cycled the vehicle before hooking it up to the analyzer. He believes it is an engine control computer problem. I agree. Based on how all the other control systems work in the 4Runner, I think the engine control software is as buggy as a June evening in Ohio. The dealer said they do not expect any updates to the control software.

Funny, you pay $100 for an MP3 player and the manufacturer provides firmware updates every couple of months until it works like a charm. Pay Toyota $32,000 for a 4Runner, and they make no effort to correct software problems, or even recognize them.

So, when it happens next, just pull off the road, shut the vechicle down, count to five or ten, and restart.

I am experiencing exactly the same problem...'03 SR5 V8, 100K miles. It's happened twice in the past 3 months. I'm going to the dealer next week. Has anyone ever figured out a fix to this problem?

Thanks, Ted

 

[ALLfor4]

Power Loss

C44Me or Anyone


I am experiencing exactly the same problem...'03 SR5 V8, 100K miles. It's happened twice in the past 3 months. I'm going to the dealer next week. Has anyone ever figured out a fix to this problem?

Thanks, Ted

 

[c44me]

I am experiencing exactly the same problem...'03 SR5 V8, 100K miles. It's happened twice in the past 3 months. I'm going to the dealer next week. Has anyone ever figured out a fix to this problem?

Thanks, Ted

Ted,

It's been quite a while since I experienced these problems, however we still have the 4Runner. Curiously, I was just thinking about this issue considering Toyota's current software issues with the Prius... Anyway, this hasn't happened to me for several years now and I believe this problem stopped occurring after we had the 4Runner in for the TSB that replaced the engine management computer. That TSB was issued in response to the exhaust smell problem that many owners reported, but I do believe we have not had the power loss problem since the engine management computer replacement. So if your 4Runner has not had that done, it would be worth looking into it.

Sorry, I don't remember the exact date or number of the TSB, but if you search around on this board, you will find it.

Hope this helps,

Gregg

 

[ALLfor4]

Ted,

It's been quite a while since I experienced these problems, however we still have the 4Runner. Curiously, I was just thinking about this issue considering Toyota's current software issues with the Prius... Anyway, this hasn't happened to me for several years now and I believe this problem stopped occurring after we had the 4Runner in for the TSB that replaced the engine management computer. That TSB was issued in response to the exhaust smell problem that many owners reported, but I do believe we have not had the power loss problem since the engine management computer replacement. So if your 4Runner has not had that done, it would be worth looking into it.

Sorry, I don't remember the exact date or number of the TSB, but if you search around on this board, you will find it.

Hope this helps,

Gregg

Thanks, Gregg. I really appreciate your quick response. I have not had that TSB applied. I will give this information to the dealer and let you know what happens.
Thanks, again. Ted

 

[RUNNINIT]

It is completely back to normal now????? I wasn't dreaming it either as I had to drive several miles with it acting like that. Do you think it could have had anything to do with the VSC because that is what it felt like....giving it gas but the VSC limiting the power to the wheels?


I don't know if I should bring it in now or wait for inspection in a month. It is not the most convenient thing to bring it to the dealer.

I would try cleaning the MAF sensor. I had this same problem I would floor the gas and it would kind of rev up but would not pick up any speed at all. I cleaned my MAF and all my power was restored instantly. Not saying this is your problem but it is very easy to clean these and wont cost you anymore than the price of some MAF cleaner $5.00 at any auto parts store.