just a guess…faulty fuel tank pressure sensor
do you also have hard starting and some stalling?
hard to know without the codes.
most Autoparts stores will scan your vehicle for free and tell you the codes. or ask your mechanic for them and post them back here. we may be able to help more than guessing.
Okay, today weird change of situation. I went on a longer distance trip of about 100 miles round trip and the oxygen sensor light went off and the mileage improved from 18 miles per gallon to almost 22 miles per gallon. Did I just need to blow out some dust or something? The Honda dealer wanted to charge me $95 for a very specific diagnosis. That seems pretty high, although at the cost of parts I do understand it. No symptoms are showing up!
Long drive, but only 100 miles!
$95 diagnostic is low, where I live $130 and up.
I guess part of your problem may come from too many short trips.
O2 sensors need to be quite hot in order to work correctly. Maybe yours got hot enough to register accurate O2 measurements during the long trip. Generally the best approach to discovering the cause is to obtain the diagnostic codes which are stored in the car’s computer memory whenever the diagnostic warning light turns on. Codes begin with letter P, followed by 4 digits. It’s pretty common thing for auto parts stores to offer to read stored codes for their customers gratis, no fee. It could be the sensor works ok as long as it is warm enough, but the sensor’s electrical heater isn’t working for example.
Why are you resisting taking the car into a mechanic for a proper duagnosis?
Catalyst efficiency improves with heat, with long trips the catalytic converter will get hotter, this can cause the catalyst monitor to “pass”.
It is normal/expected for the fuel economy to vary with different driving conditions, the CRV is rated at 21 mpg city/ 28 mpg highway.
Post # 6 states that the problem has been diagnosed as a failing catalytic converter.