1997 Chevrolet Monte Carlo Q&A
1997 Chevrolet Monte Carlo Question: emmission codes
do u know what the code po121 means for 97 monte carlo 3.1 v6? or po420 on 98 merury sable? - Visitor
The p0121 on the monte carlo is a throttle position fault. More testing would be needed to determine if the sensor is actually bad. The p0420 on the mercury is a catalytic converter fault. Most likely indicating the converter should be replaced. - kwmk
we know where the knock sensor is...can't quite figure the best way (least invasive) to approach and replace it...have a diagram, but it's not helping....can you give us an A,B,C hint as to how to ...