my 1991 honda accord is reading these codes 12, 17 and 20 does anyone...
 

...know what they mean? i got these codes today on my 1991 honda accord the problem iam having is that its loosing power all of a sudden when iam driving or when i come to a stop sign and take off it doesnt want to go it pulles back then all of a sudden it takes off what does that mean? i just did a hole tune up about a month ago?

The 12 means that your car is no longer safe to drive and must be junked. If you were to get in an accident and the police knew you continued to drive the car after a code 12 you could be arrested and the penalty is much larger than DUI. Good luck I have no idea what the other two codes mean. Usually the 12 come on by itself.

You should go to the service shop to check the codes.