Chosen Solution
My car randomly idles pretty high (around 2000 rpm) and I’ve noticed my mpg has suffered. I only got about 250 miles out of a tank of fuel. I like to think I drive pretty sensibly. I had the check engine light scanned and it came back with evap system small leak p0442 and catalyst system low efficiency bank 1 p0420. At the top of the printout for the engine light it says “ASE certified mechanics have seen this issue on your type of vehicle and the most likely solution is replace fuel tank pressure sensor. I was ready to do this but I was told that the fuel tank pressure sensor doesn’t affect how the engine is running. Could the idle and poor mpg be the sensor? A vacuum leak? Something else? The car otherwise is strong and has no knocks ticks or other issues shy of a broken exhaust hanger. Please help.
@dustinrulo1988 the P0420 code actually has numerous causes of which all of them could be the cause of your symptoms: Fuel injectors may be faulty Fuel injector leaks Spark plugs may be faulty Improper ignition timing Powertrain Control Module (PCM) Three way catalyst converter Bank 1 Intake air leaks So, I’d start with the easy one, which would be your plugs and checking for air intake leaks. Most common issue is a failing catalytic converter. Also, you do want to check your O2 sensors and see if they need to be replaced.
