ok here is the problem...i have new d.s.s 306..x303 cam...vic jr. heads...and intake...24# inj...255lph pump etc...full length headers...1.6 roller rockers..i am having problems with spark knock...its almost like it is backfiring...if you give it gas while idling then let of and gas it again it will backfire...and the car doesn't seem to have power.. i tried lowering the timing to 10 degrees...same thing...then i went to 12 and on to 14...the wierd thing is that the car runs better if i go up to 16 to 18 degrees...by the this is with pulling out the spout then setting the base timing to these numbers...i don't have a chip yet...but i know it should run better than this...my question is could the timing be different since its an x cam...and could the TPS cause this kind of problem...the o2 and act and ect sensors are all new...thanx