My above mentioned car is always struggling to get going as if the car is too big for the engine. I am noticing this especially when going up hills. The engine runs on gas or petrol and i do notice a small increase in power when switching to petrol but it is still very sluggish. There seems to be alot of get up and go in 1st and 2nd gear but on hills 3rd gear it struggles and i usually have to change down to 2nd. Could this be a lack of compression ? or is there something i can do to increase power ?