Hey Toyota Techs, I have a 2000 Toyota 4Runner (148,000 Mi) with an inconsistant miss. Went to the local mechanic with the engine light on with a P1133 code and he replaced the front CO2 sensor. This didn't seem to correct the inconsistant miss. The engine light came back on showing the same code. Went back to the garage and went through the ignition, found a black arch on the drivers side center spark plug. So he replaced all the plugs. Left, it initially seemed to run well for a short time, then the engine light came back on and had the same type of miss (mainly under load). Went back and replaced the spark plug wire leading to that plug and replaced the plug. This intially seemed to improve but a day later the light came on again with the same P1133 code and seemed to be losing power accelerating on hills and in load situations. I decided to go to the distant Toyota dealership and have them run diagnostics. Their tests showed that there was no specific cylinder missing but all coils showed a low KV reading. Their recomendation is to replace all coils, wire set, and plugs, at a cost of $455 +tax. After I left the dealership the truck ran seemingly well coming home with occasional miss and the engine light is back on. Does this sound logical to you that all 3 coils should be replaced? The coils and wires are all original parts. My mechanic did put in regular plugs that the book called for but Toyota said that they needed the "dual post" plugs and needed to be replaced. The catalytic converter has been replaced. I would value any insight you have with this mysterious miss.

thanks, MTNrunner

 

Did anyone check your injectors? They have a history of failing. I've never had to replace 3 coil packs so I think it was a bit extreme for the dealer to do that. Thats why they are who they are...

 

I agree, I had a dealership tell me fuel injectors don't go bad. They will never assume it to be an injector. If you know how, you could get an Ohm meter and test your injectors.

 

I wrote this up awhile back on checking fuel injector #5. The same applies for all of them, although you will need to remove the intake plenum to get to the fuel injectors on the driver side.

First remove the air intake tube


Second locate the #5 fuel injector


Next unplug the the fuel injector clip


Last test the resistance on the fuel injector.

 

also too, if you have a stethascope or even a long screwdriver, you can listen to the injector while the motor is running and tell a difference in sound. Matco makes a very handy tool I use when checking injectors. Its electronic and has a long slim probe which when turned on can sense the slightest movement. If the injector is working, it lights up and makes a beep on each fire. If it isn't it wont come on at all. Of course you can find someone who has a set of noid lights to make sure there are pulses at the connector side

 

The dealer may have been a bit extreme in parts replacement, but at least they put in the right parts which is more than I can say for your other mechanic that put in the wrong plugs. That being said, I also suspect the mechanic probably put in the wrong O2 sensor (actually it should be an Air Fuel A/F sensor not a standard O2 sensor) so you'll want to change that as well unless you can verify he got the correct one from the dealer. Finally get the code read again to make sure it is in fact the same code again and not something else.

If the same P1133 code comes back, your options are:
�� Open or short in A/F sensor circuit
�� A/F sensor
�� Air induction system
�� Fuel pressure
�� Injector
�� ECM