What would your punishment be for your 16 year old lying to you?

I have a 16 year old son that has a bad habit of lying to not get into trouble. He did it again last night and I gave him a chance to tell the truth and explained like always it is better to just get into trouble for what you did instead of for lying too. I gave him until bedtime to confess and he did not. He was not able to drive to school today as a result and during the day he confessed. He thinks that since he did confess he should not be punished any more. I explained he is being punished for lying more than for what he did. He took his dads truck mudding last night and tried to wash it all off with not much luck. He never washed the truck or our cars on his own and I could see the mud in the door frames so I knew right away what he did and told him. He denied nd said he went through a puddle. We went for a drive to show me the puddle and I didn't see one. He said it dried up. Lol Anyways, I was not happy about what he did but just wanted him to be honest instead of lying. I have always told him It is better to just tell the truth and things would be much easier. I feel bad with it being the first weekend of summer but he needs to learn. I wanted to ground him for the weekend but my husband thinks it should be a week. What kind of punishment would you give your son if he did this?