I havnt had te 172 for long but since owning it I have given it a full service including plugs, it's seems to run fun until you boot it then it doesn't seem very fast at all, doesn't really pick up much until you get through the revs in 3rd but it still doesn't seem fast, even tried keeping up with a old civic type r but I had no chance, my car has got 4 branch exhaust manifold, decat and full s/s system, induction kit, and ment to be remapped, race clutch, light weight 16s, the only thing I can think if being at fault is the intake manifold gasket was abit old and the bolts didn't seem to tighten up well when fitting the plugs so it could be leaking, has anyone had any problems with this before ? Thanks