ok i have a 03 cavy and last week i had a p0300 (random misfire) code pop up replaced the coils then found out it was the ICM that was bad...so got the one from napa. the missfire is gone, but after i cleared the code at autozone i went to work and after work i noticed the CEL was on again. so today i took it back to autozone and a p0172 (system too rich bank 1) came up. i run 91 or 93 octane fuel, the cavy only has 41,xxx miles on it, and it is completely stock minus the spark plugs, and the replacement parts i just mentioned. i replaced the spark plugs about 4000 miles ago (in october) and i could tell that it was running rich then cuz they was black and smelled really bad of fuel. autozone said it could be the MAF, O2 sensor, injectors, misfire, or a vacuum line.

any ideas

thankx guys

jk

Sounds like 1 primary O2 sensor is shot. Needs replacing, Could take a look at the wiring harness, It could be messed up. Or you just got a faulty O2 sensor.

But wouldn't the O2 sensor throw its own code/

ok so i checked prices on o2 sensors and do i need a rear or front one....i looked under the hood and under the car and can only see one behind the cat. and if there is one in the front of the cat where is it....and is there anyway i can check the o2 sensors without spending 80-100 dollars on one???

thanx guys for ur help so far

jk