Also i was studying the engine layout with this engine have two seprate chains not a single main chain. In reality this engine is really set up as to separate 4cly engines running on a single crank there for if i get a cam gear to walk a degree because of slop on the cam shaft or gear key way. It could get out of time. The ecm would not detect it because the engine fires off the crank .I will have them to check ecm too if they did not do it and i am replacing injectors