Hi, I just joined this forum to find out cost of repair on 2008 HCH. I bought used 2008 HCH in 2012 at 60K miles and drove 60K miles on it. Till 120K miles, it has not given me any major mechanical problem and kept average 45mpg even with harsh winter in NE. A few days ago, the engine light came on and the OBD was showing the code P1172 (Fuel/Air ratio sensor fault). The car was driving fine, but I dropped it off at a dealer, and they quoted me with $425 to replace the sensor (PN 36531-RMX-A01 retail price at $342). I know I can get this part cheaper on-line, but I didn't know if I wanted to try installing it myself, since I am not so mechanically inclined. Would it be difficult to perform DIY for someone who have never worked on a car? Additionally, the dealer recommended to replace spark plugs, inspect valve clearance and replace valve cover gasket for additional cost of $500 plus tax. The price seemed to be outrageously high for just those two things. What would be average cost of spark plug replacement on this vehicle. I have never replaced spark plugs on this car, so it must be still running on the original ones. Does it really need to have spark plug changed at all if it is not showing any problem? What other maintenance need to be performed on HCH with this mileage beside oil change? Thanks in advance for your advice.