i just bought my 91 civic hatch back for 350 $ and the only thing wrong with it is that it seems to have a power loss somewhere...and if i rev it up to a certain point like 3500 grand it sounds like something is blowing out the exhaust collector... and when i am driving it it drives well in first than 2nd it boggs down a little bit than 3 it is gutless.... any suggestions? and this is a brandnew engine could it be a vacuam leak?