2002 Trailblazer Lt 12 MPG Code P0420
Getting terrible gas mileage for at least half a year or more (didnt check till now).
Have had the code P0420 for months as well. Finally decided to try to fix this issue and purchased two new delco pre and post oxygen sensors.
Installed and still get 12 mpg and the code pops up. Also has the regular tune up done (filters,oil,plugs).
Thing is the truck does not drive badly and so have not put it at a priority to fix the light. However, the gas mileage i have researched i should be getting 15mpg? Am i right?
If so how do i proceed?
Ive read it can maybe be my coolant temp sensor, should i replace that less expensive part along with the thermostat? Temp reads slightly left, the next click to the left of 210 and sometimes goes straight up so i doubt its that.
Re: 2002 Trailblazer Lt 12 MPG Code P0420
Yes clogged cats will hurt your mpg's and no throttle body cleaning will not make your mpg's any better. Just make it idle run better.