Primo

Hey everyone, it has been a while since I have posted but I am having an issue and I am hoping someone can help. I am the original owner of a 2000 4Runner that now has 115,000 miles. I have lifted it, supercharged it, had the tranny worked on and all maintenance and the truck has just been awesome.

Well, I was getting a CEL and had it read at a local Auto Zone. They gave me the codes P1130 and P1135. The gas mileage on the truck had been getting worse as well.

So, I did a search and came up with the A/F sensor on the upside of Cat 1 being the potential problem. I ordered the Denso part number 234-9002 which is for the CA spec 2000 4Runner. I installed it yesterday which is no big deal (two nuts and a plug) and then pulled the EFI fuse as I have done in the past. I took the truck out last night and it did not want to drive. It started just fine with no code but after going a few miles it did not want to take gas. The truck would seem like it wanted to stall. I had to pull over twice with my hazards on to let cars behind me go by. If I tried to give it a lot of throttle it would smoke and shudder. There seemed to be times when it felt close to normal but for the most part it was terrible. What the hell happened? All I did was change a sensor. Is this the ECU trying to relearn or is something else wrong? I only put about 6 miles on the truck but I am afraid to drive it.

Before the swap, the truck ran fine, I just had the CEL and bad gas mileage. Has anyone experienced something similar?
Thank ahead of time,

Rob Primavera

Robb235

If you look under your truck, do you have 1 catalytic converter or 2?

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Primo

I have two cats and I have checked the emissions sticker under the hood. The truck is definitely a CA spec vehicle and the sensor that came out was identical to the new one. I am sure it is the correct part number.

Rob

Robb235

Gotcha.

Not to insult your intelligence, but you did plug the new sensor in, right? I know sometimes it's easy to bolt the thing in, and then forget about the plug.

Do you have access to an OBD2 reader? A handheld, maybe a Scangauge or one on your phone? Would like to see what values the ECU is reporting for the front O2. Any CEL on? Sent from my iPhone using YotaTech

Primo

Not insulted at all. I have made stupid mistakes in the past but the plug is definitely in correctly. I also cleaned both sides with contact cleaner before putting it back together. Unfortunately I have no access to an OBD2 reader beyond what the local Auto Zone can read for me. The light did come on again last night during my drive. When I got home I pulled the negative cable on the battery to reset everything and will reattach this morning. Could it be a bad sensor? Not like you can put it in wrong.

Rob

Robb235

If the light comes on, get it scanned and see what the code is.

An OBD reader that can show live ECU data would be the easiest way to diagnose. Really need to see what values the front O2 sensor (AFR sensor in your case) is reporting.

Does the truck run like crap when its first started up and still cold? Does it get worse when warmed up? Or does it run like crap right when you crank it up?

I feel confident you have the correct AFR Sensor, your part number you listed is the same one as for my '99 Cali spec.

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Primo

Well I had a chance to take the truck out at lunch. I did about 40 miles. It starts and idles just fine. I notice the problem now mostly on the highway and when a load is on the vehicle. For instance, getting on the highway at a long gradual hill it seems when I try and maintain throttle it doesn't want to go and thick black smoke pours out the exhaust but if I floor it, it seems to go okay. On this particular hill, after previously driving for 25 or so miles the CEL came on again. Seems to drive fine around town at low speed. I don't get it. I will have the new code read tonight and see what it says. I am about to put the old one back in. It ran fine before the new sensor!! Frustrating.

Rob

Robb235

See what that code is and post up the number they give you.


Switching back to the old sensor wouldn't be a bad idea. See if things go back to normal.

Primo

So, I have been a bit frustrated and I need my truck so I went out this morning (20 degrees) and changed the sensor back to the old one. I did not have a chance to get the new code read. At lunch I got to take the truck for a ride. After 3 miles the CEL came on but the truck ran just fine. No black smoke, no hesitation, just the engine light. I packed up the new A/F sensor and dropped it off at UPS. They are sending me a replacement. So, I guess I will see what happens when I bolt a new new sensor in. I don't get it!!! I am hoping I got a bad one because if the replacement makes the truck act the same, I am at a loss.

Rob

wyoming9

iTrader: (1)

If your going to have one of these OBII vehicles and do any work your self not having at least a code reader to me was very frustrating .

I now have one in each vehicle of course the MIL has not been on once but it is nice for reading other peoples codes.

Even Denso makes a defective product once in a blue moon.

Primo

So I thought I would post the conclusion to my A/F sensor issue. As some of you know, I was receiving codes P1130 and P1135 which pointed to the A/F sensor. My truck is a 2000 Cali spec 4Runner. I bought the Denso sensor part number 234-9002 and replaced it. A bit of a pain only because the nuts were rusted completely so I had to use locking pliers to get them off. I did buy new ones. So the truck ran like complete s@*t with the new sensor. I had to pull over twice on my first drive as it just would not take gas and would bellow black smoke out the exhaust like crazy. I needed the truck so I said screw it and put the old one back in. With the old one the CEL came right back on but the truck seems to run fine with the exception of terrible fuel mileage.

I had purchased the part from Amazon so I thought I would return the one I bought for an exchange and if I still had issues I would dig deeper. Well, Amazon was great. I had the new new part at my house in just a few days and it was free to return the first one. Back under the truck, I again swapped the sensor. Good thing it is easy to get at and just two nuts and an electrical connection. I am happy to say that after a few hundred miles it appears that the first Denso sensor was bad because the truck has been running great with the second one. I wanted to give it a while but I will start to track my mileage. I believe it should be a bit better. No more CEL which is fantastic and hassle free exchange with Amazon. I am a happy camper. So keep in mind that even Denso can make a faulty part once in a while.

As always this forum was a big help. Thanks!!

Rob

vasinvictor

iTrader: (3)

I'm betting your problem will return... EXTREMELY doubtful that you got a bad sensor and the second one fixed it. Here's to hoping though...