My timing was replaced by my neighbor and he swears it's done correctly but it won't go past 4000 rpm. It's Either not timed right or something else. He swears he timed it right. If the timing is off would it effect the VTEC solenoid? Will the timing effect vtech?

 

if the only thing that was changed was the timing belt, it is possible the timing is one tooth off. Put #1 piston on compression TDC and check the alignment points for the cam and crank should not be hard to do. if you can view a few utube videos of timing belt and alighnment, .

 

he also put a header on the exhaust could that be the problem

 

header on the exhaust only makes for a better exhaust gas flow.. might also check your cat.to see if its is plugged. .