When I put the blower speed on level 4 I would expect it to blow really hard but it doesn't feel very fast. It progresses through all of the speeds ok bit its almost seems as if its blocked somewhere Any ideas?

 

Do you have AC?

Look under the glove box if you do. There is a black box. Inside is the evaporator core which looks very similar to a very thick radiator. I bought a used one a while back and after taking the black platic box off, I found a LOT of cat hair and cigarette tar build up on the fins of the core. Yuck to say the least. Blockage for sure.