Hello, recently the check engine light on my wife's 03 Accord EX v6 has been coming on intermittently. We had it checked and received the codes 172 and 175, fuel banks 1 and 2 too rich. Doing some research, she added some fuel injector cleaner the next time she gassed up. It went away for a day or so but is back to coming on intermittently. Last night, we dropped it off at a mechanic, who gave us the following diagnosis this morning:

MY NAME IS DYLAN I AM THE SERVICE MANAGER HERE AT GASTONS GARAGE AND I AM EMAILING YOU WITH WHAT WE HAVE FOUND OUT WITH YOUR HONDA.....WITH FOLLOWING OUR DIAGNOSTIC PROCEDURES WE NEED TO DO A VALVE ADJUSTMENT. ACCORDING TO HONDA THE EXHAUST VALVES TEND TO TIGHTEN UP AFTER A PERIOD OF TIME AND DO NOT ALLOW ALL OF THE EXHAUST TO BE RELEASED FROM THE ENGINE CAUSING A RICH CODE AND CONDITION IN YOU VEHICLE.ALSO WE NEED TO PUT MORE FUEL IN THE VEHICLE TO DO AN ADEQUATE TEST DRIVE.. TO START WITH ALL OF THIS YOU WILL BE LOOKING AT A COST OF $685 TO START. FEEL FREE TO EITHER CALL OR EMAIL ME BACK AS SOON AS YOU CAN PLEASE

Does anyone have experience with valves causing this problem or other ideas on what the problem might be, as they don't seem very sure.

Thank you for any assistance.