It worked one night, next morning engine light came on when I started it and ran like poo. I had someone look at it and they tried telling me its my injectors. I found that a little tough to swallow as it happened literally over night and to 3 cylinders. I have since cleaned the injectors thoroughly, cleaned out the throttle body and made sure my fuel line was clear. I also replaced the fuel filter. Now I'm at an in-pass. I'm thinking perhaps my timing belt needs replace, or is it something else. Truck has 150,000 miles and is my work truck. Any assistance would be very appreciated.