pdxrunner

I have a 2002 4Runner, 32k miles. Lately it's been hesitating during acceleration at low or no speeds. It even stalled on me the other day as I was accelerating out of a 5-10 mph turn.

I should also mention that I have a TRD supercharger in my runner too.

It stalled on me the day before my 3-year warranty expired. I made an appointment to get it looked at at the dealership.

It's been there for over a week now. They've replaced the fuel injectors (which helped minimally), and today they've replaced the airflow gauge/meter. I am waiting to hear back from the service rep today.

The only other symptoms I notice are that it sometimes hesitates when shifting between 2nd and 3rd or 3rd and 4th. Almost as if it should have shifted already, but hasn't. I have to fully remove my foot from the gas to get her to shift.

I've been using 92 octane gasoline ever since I put the charger in.

Has anyone else experienced anything like this?

Thanks,
Patrick

pdxrunner

Seconds after I posted, I got a call from the service rep and he told me (and I'm paraphrasing, of course) the following:


They've replaced the fuel injectors, and 3 major components including the air/fuel ratio meter and it isn't running any better. He said they put the new meter in and after 30 minutes, they took it out and it was covered in soot.

He also mentioned that it is just running "way too rich." They keep ordering components in the fuel system and replacing them with no luck. This time they've ordered a new main computer which, "never fails. They're military grade." They'll try that tomorrow and get back to me then. He said that they believe the problem to be electrical.

I asked him if having the supercharger on there could have anything to do with this and he said no.

I'll post follow-ups as I learn more, but I sure am glad that this is under warranty.

Still anxious to see if anyone else has had a similar experience with their 4runner.

pdxrunner

Here is where we are now. Service rep called today and they've replaced the main computer. They can now get it running really good as long as it's above 3000 rpm. Below that, it's not very good. If they let it idle for more than a minute or so it starts running very rich again and the plugs get all gunked up. They take them out, clean em off and clean the system and do it again and it continues the same way.

They've been in contact the whole way with the tech people and they are now out of ideas completely.

The rep said that they are bringing in another 4runner just like mine next week and they are going to start taking parts off of my truck and put them on the other 4runner until they get the other one to run like mine and then they'll know what part was the culprit.

So, this begs the question....what if they can't make it happen? It's under warranty, would they try and get me another vehicle with the same features same mileage as mine? Would they pay me the blue book value of the vehicle? I'm sure something like this has happened in the past. Does anyone know of a precedent in this scenario?

pdxrunner

Just spoke with the service manager, as my rep is out today. They called a guy in from TRD to take a look last Friday. On Saturday, he was finally able to get it to set an error code. It seems that the problem is the throttle body. I think they'd already replaced the TPS, but there was something wrong with the throttle body.

That part has been ordered and should be in by today or tomorrow and maybe this will fix the problem.

That's all for now.

pdxrunner

The service manager wasn't correct in what he told me. After gathering more information, it's the Throttle Position Switch that was bad. They were able to get one of them the next day, but because of my supercharger, they needed a special gasket from TRD. Evidently, TRD must not have any supply warehouse, because it took them a week and a half to get the part here.

It arrived yesterday afternoon and they are reassembling my 4runner right now. Service rep thinks it'll be ready today. We'll see.

For those keeping score at home:

5/11 truck dropped off
6/10 (today) truck might be ready

If this doesn't fix it, they'll have to go back to the drawing board, but the service rep is pretty confident given that the technician was able to get the main computer to set an error code.

I'll post in the next day or so with an update.

Ironmike4x4

Dang I hate when we get ones at the shop that is almost impossible to diagnose. One we had about a month ago, we wound up trading the vehicle with them. I don't know how they will do it though. Hope it works out, just keep us updated on what the problem was when they figure it out.

pdxrunner

Let me start by saying that despite the amount of time, they were very thorough with the repair.

Here is what was written on the work summary:

Parts:
6 Fuel Injector Set
1 Air Surge Gasket
1 Vacuum Hose
1 Air Fuel Sensor
6 Spark plug
1 Throttle Body Assembly
1 Throttle Gasket
1 Air Filter
1 Oil Filter
1 Element Sub-Assembly

Description:
Injectors leaking causing extreme rich condition. Also air fuel ratio sensor not responding due to gas. Spark plugs fouled gas in crankcase had no codes on arrival. After subst. ECM performing check on supercharger finally set code PO120, Lost reading from TPS.

Replaced all 6 injectors ran fuel pressue test 35-40 PSI. Removed timing cover. Check out crank sensor (okay) valve timing okay has 175 PSI compression replaced fouled plugs also replaced AF Ratio sensor ran okay sometimes. Checked pins in computer & all grounds (okay). Got code PO120. Replaced Throttle Body & installed TRD Gasket decarboned

===========================

Aside from the initial symptoms with the poor acceleration and stall, they also noted that it was shifting very poorly. Driving it home from the dealership, I was shocked to see how poorly my truck had been running. It was shifting so smoothly and was accelerating perfectly. Really amazing.

Now, when I got in my truck at the dealership, they had no used the paper protectors to protect the car mats very well, so I took it in and told them. They gave me a brand new set of floor mats.

When I got home, I noticed that they had broken my bug guard on the front. I called today and the service rep told me that he had already ordered another one, but forgot to tell me about it. It will be in on Wednesday.

Service rep also mentioned that the computer had been 'taught' some really bad performance with it running so rich for so long, so they erased the memory of the computer. He said it'll take some time 100-200 miles but it'll keep running better and better as it learns my driving style, etc.

Alls well that ends well, I guess. I can't believe it took a month for these repairs, but since they couldn't get the computer to set an error code, there wasn't much they could do. I was told that they had 2 technicians out working on it at one point trying to figure it out.

Anyway, hope it runs well from here on out.

paranoidandroid

Wow. the day before your warranty expired....so lucky. Also, I havent heard of a dealership that was so good, ie:

1) gave free floor mats
2) ordered new bug guard
3) most important: CONSTANT COMMUNICATION?!?!

I am impressed. Glad they found the problem finally though.

pdxrunner

I've had my truck back for about 3 months since this problem was resolved. She was running really nicely for about 2 1/2 months and this same behavior began again. Identical to the last time.

Bogging during acceleration. Feel's like it's going to stall, etc. It's particularly bad trying to accelerate from a stop on an incline.

Fuel starvation issue?

Anyway, I had an appointment this morning to drop her off to have them take a look at it. I can't imagine that the Throttle Position Switch would have gone on me again.

I'm supposed to hear back from them today. I'll post again with more information. I hope it doesn't take another month to get it fixed this time.

pdxrunner

Just spoke with the service rep and he said that it's behaving exactly the same way as it was 3 months ago when they had it. They are cleaning it up for me so it will run better the next few days, but he asked me to take it back in on Wednesday, 9/16. They're going to give me a loaner car while they run a battery of tests on it to see if they can diagnose the problem.

He also led me to believe that since this is the same problem as last time that Toyota would still cover this as it was a pre-existing condition while my warranty was still valid.

Anyway...more updates to come next week, for sure.

Ironmike4x4

Dang I'd hate to be that technician working on it since he gets to do it for free pretty much. If it keeps up then you might just wind up with a new vehicle!

Crux

Wow, that sounds like a real lemon.
Hopefully they can figure out what the real problem is!

pdxrunner

Thanks for the sympathy, guys.

So, I took her back in on Wednesday 9/21 and they gave me a loaner. I spoke with the service rep Thursday afternoon and they can still demonstrate the behavior and they still don't know what to do. He wants to pull the supercharger off of it to see if that has something to do with the problem, but that's like 6 hours of labor and he can't put that kind of money into it without getting authorization from Toyota that this will be done under warranty as a pre-existing condition.

I'm in an interesting position. I'd love to have it fixed quickly, but more than anything I just want to get it fixed. Since I'm not willing ot open up my checkbook to get this done (and I shouldn't have to) I'm kinda resigned to letting them fix it on their timetable.

They are only able to work on it from Wednesday - Friday because the service rep is not in on Sat - Tue. This is a little frustrating, but understandable. They're going to have me come in and drop off the loaner tonight and take my truck home for the weekend and then we'll do it all over again on Wednesday.

It kills me that they don't know what to do to fix it. It's not like I'm asking them to cure cancer here. It's a truck!

Localmotion

that is insane!!!! you need get on them about fixing your truck! If that was me....3 months of working on it and still not fixed is unacceptable!!! start writing letters to toyota and to the dealership.

EDIT: 4 months!

Localmotion

ps...i would talk to gadget, he seems to be the one to talk to about this stuff....Im sure he knows more then the toyotech guys.

http://www.gadgetonline.com/

garrett1478

i don't get why the dealer automatically 'knew' it wasn't anything to do with the supercharger. have you done any fuel mods to your truck since installing the supercharger? if i were you, i'd PM gadget and tell him to read this thread, he knows the most about supercharging 4runners and getting them to run top knotch. good luck!

MTL_4runner

You need to hook up an OBD II scanner to that vehicle to be able to see what is really going on. That was you can see everything the sensors see and how it is actually operating under various conditions. You can see when this rich condition occurs and what fuel trim results if any. Just looking for codes and parts replacement (like most dealers do) is not likely to fix this condition. Replacing the ECU is a joke, they NEVER go bad unless you get them wet (I only have seen 1 go bad and it was heavily corroded by salty water....go figure) and even then they rarely fail when dried out.

Also remember even if you are not opening your checkbook, you are still losing money on a vehicle which depreciates while you don't drive it.

snap-on

perhaps, but even if you were driving it, it would be looseing money even quicker as your adding more miles to it.

Ask for a loner 4runner and tell them youll drive it till they get yours fixed. Nothing like driveing someone elses brand new car for another month

pdxrunner

I sent an email to gadget this morning. We'll see where that goes. I've done no fuel mods to my truck whatsoever. The only things I've done were adding the supercharger (done by the dealer at 3k miles), putting on Bilstein shocks and Xenon headlights. No other mods were made.

Thanks for the advice.

Also, I spoke with the service Rep on Friday morning and they have an engineer coming out from Toyota to work on it Monday, 9/26 (today) and I will get an update on Wednesday on his progress.

Gadget

They are never going to solve this problem by throwing parts at it. They need to do a logical diagnostic process.

Step one would be to find out if all this extra fuel is being commanded by the ECU to be injected or it is happening without being commanded. Once that is determined the cause should be easy to find.

If it is not being commanded by the ECU it is likely a stuck injector or a wire harness issue allowing one of more injectors to short to ground and stick open. The harness can be checked with a simple Ohm meter or a duty cycle meter or even a cheap Noid light. If that checks out then it is likely an issue where the ECU is commanding the injectors to inject to much fuel.

If that is the case, there maybe a fault in one of the sensors, like the MAF, air/fuel ratio sensor, ECT and so on. This is real easy to track down by simply looking at the data stream from the ECU. You can quickly see if one of the signals are out of range and throwing everything out of whack.

Or of course they can just keep throwing parts at it.

From your description I can see they did check fuel pressure. They may not know it, but that is a diagnostic step instead of a parts swap...

Do keep us informed on this and what it ends up being. I will bet you a box of donuts that it is something very simple, like a wire harness issue.

Gadget