QuestionMy 2000 4runner had a check engine light with a obd code of p420. I took out the MAF and cleaned it very well, out it back together, reset the code and it ran fine for about 2 weeks. I then got another check engine light. Don't remember what the code was but the internet was saying that the catalytic converter needed to be replaced. Other posts on the internet was saying to replace to O2 sensor. I kept resetting the code. It would stay off for several days and then come back on. Finally I got the code that says the O2 sensor was bad. I replaced the pre cat O2 sensor. The check engine light has stayed off this time, but the truck idle is bouncing and it sounds like it is going er er er to get up to speed. Also I gas up every day from my commute which used to be 5.2 gal to refil, now it is close to 6 gal. Can you help with this.
Thanks,
Nevr2late
AnswerWes,
First of all those sensors are there to tell the computer(ECM)
that something is off in the emissions systems. It DOES NOT mean
the sensor is bad. Something is causing the engine to run rich or
lean. 02 sensors GET dirty, they can be cleaned,its a lot cheaper then replacing one.
If plugs are worn, if an air filter is dirty they can set off
a sensor.
How many miles are on the vehicle? What year? Auto or 5 speed?
A good technician with a expensive code scanner can pinpoint the problem. Sensors can be checked with an ohm-meter. Because I'm not at the vehicle it makes it much more difficult to solve. It's like a surgeon trying to operate on someone long distance.
Start by checking all vacuum lines, plugs, ignition wires, etc.
Tim
