PLENTY LEFT IN THE TANK SIR

A message to you I have plenty left in the tank sir 
You don't have to worry about me this I can concur  
I have walked a great distance that is for sure  
Plenty left in the tank sir I can walk a good deal more  

Climbing up mountains is no problem for me
I'm as fit as a fiddle sir as you can positively see
I can drive miles and miles without getting tired
I have plenty left in the tank sir which should be admired 

So you can see sir I will meet any challenge coming my way 
Driving,climbing,walking it doesn't matter to me I say 
I will say it once more I have plenty left in the tank sir  
However you can take my place if you prefer