What is the significance of the Malfunction Indicator Light? on 2002 Acura MDX

This light comes on periodically and then goes off after a few days (usually when I take off the gas cap, it goes off around the 3rd or 4th time). The service people tell me if it starts flashing that I have to stop driving the car immediately. So far it has never started flashing. This has been going on for over a year. The car seems to be running fine. I spent hundreds of dollars in service fees to fix it but it still comes on.

Asked by for the 2002 Acura MDX
Next time you have it in for service , get the specific trouble codes (DTCs) and reply with them on this post. We'll be able to help better with them. I suspect maybe one of the following; P0456 , P0457, P1456 or P01457. Lots of other possibilities though. Is it Acura/Honda dealer or independant shop?
Acura dealer
They have NO excuse for not getting it right! If you've paid for diagnosis and repair for that issue I would hold them to it if they say it's going to be fixed , then if the code returns it should be warranty, unless they have a valid reason for the failure(s).Next time your in get the code(s) and post them on this thread , Honda codes are the same ,as are their diagnostic and repair procedures.
The DTC code is PO301. The light went on again today, and I took it immediately to the dealer while it was still on. They hooked it up and that code came up. Please advise. Thanks.
1 more answer , 1 more comment
po301 is a misfire code...have them check that...
Yes, that's what they told me. It's good to know that you are confirming what they told me. They showed me the monitor that indicated #1 misfire, PO301. It's interesting that it is misfiring because they put all new spark plugs in the car in 2010 when it had a little problem starting (that occurred before the malfunction indicator light ever started coming on). Car is still in the shop, so I'm wondering what is taking so long. When I left it, they indicated it should be a pretty simple fix.
Thanks for your help.