- Jan 5, 2012
- 321
Had this code come up today. I have 185K miles on the truck and never replaced the O2 sensor(s) or CAT.
How should I go about diagnosing the issue? I saw Chickenhawk's post about checking the pressure (I would have to buy a pressure gauge, no big deal). I feel like it does struggle a bit on acceleration, but I can't be certain. I drove a 100 miles today back from work and I calculated the MPGs. The DIC indicated 20.5 MPG, actual miles/fuel consumed showed 20.8MPG, so I feel like I can trust the MPG's are in that neighborhood. This has decreased from the 22 MPGs I used to get a couple years ago, but again could be the route, weather, quality of fuel, tire tread...
So what steps should I take in diagnosing this?
How should I go about diagnosing the issue? I saw Chickenhawk's post about checking the pressure (I would have to buy a pressure gauge, no big deal). I feel like it does struggle a bit on acceleration, but I can't be certain. I drove a 100 miles today back from work and I calculated the MPGs. The DIC indicated 20.5 MPG, actual miles/fuel consumed showed 20.8MPG, so I feel like I can trust the MPG's are in that neighborhood. This has decreased from the 22 MPGs I used to get a couple years ago, but again could be the route, weather, quality of fuel, tire tread...
So what steps should I take in diagnosing this?
It's not 4:20 or anything about "trees."
It's an OBDII code P0420. 

