Ok i just had the new exhaust put on i got the car back 2 days ago now it smokes when i give it gas, like blueish color if i give it gas then let up it puffs out...I had long tubes,off road H-pipe and cat back plus an air pump delete pulley and all emission stuff removed....I also notice oil residue in the tailpipe...It never did this before....what can be causing this.....????