I have a 5.4 and the truck wouldn't stay running, the check engine light came on and the code was cam position sensor, I changed both and still didn't fix the problem, I took the truck to the nearest dealership and the variable cam timing actuators needed to be replaced and the mechanic said there is sludge in the engine. If replacing the actuators makes the truck run smooth again how do I get rid of the sludge? Do I need to try to get rid of it? I've heard some sludge can help seal and stop oil leaks, it has 135000 on it I bought it used with 89000 on it I keep the oil changed regularly, any suggestions?