i took it to a mechanic with 40 years experience...before he even opened the hood he started it up with me in the car, 93,4.0 explorer pushrod and he immediately said my fan clutch is going out, said its running to fast, he hears a whooshing noise.. said it will be from $150-300....said its a emergency before it destroys everything but this guy works at a junkyard, so is he right? also , the engine is quiet like it was 15 years ago, i hear no pinging or clicking noises, and when we test drove it he said one of my cylinders is not working causing the heavy vibration idle and slow acceleration? then he said that using a k&n air filter like i did for 10 years has ruined my engine and told me to buy a new truck? he said the kn filters let to much dust in and that its a grinding compound that scratches the engine and causes more blowby? said to switch to wix filter premium i cleaned the kn filter every 6 months and it was hardly dirty but my throttle was smothered in cake like carbon crap and the intake tube and manifold had wet oil in it about a teaspoon and he says this is from excessive blowby and my engine is ruined? yet it runs great and real fast until my clutch or differential went out last week..still needs to be fixed does this guy sound right or not? im going to be switching to 410 gear this week for $650, and buy a new fan clutch and new tps but he says my engine is ruined and that im wasteing my money? when you start it up, you see about a 1 second white smoke come out of the exhaust but then its clean...do i need a new truck?