OH... all Duratec engines have a problem that sounds like bad valves. Use a mechanic's stethoscope trick and listen to the intake manifold and the valve cover. You'll quickly find out that the sound is coming from the intake and the valves are super quiet. This is due to the "tumble flaps". Some people have had problems with the tumble flap shaft penetrating the intake manifold and causing a vacuum leak. I have not had that problem and my flaps have been clacking away for more than 50k miles now.
To repair, the intake manifold should be replaced for about $300 with a new intake manifold. You might be able to find a used intake for $100, but that's getting more and more doubtful in these later years.
I find these cars for sale all the time fairly cheaply because someone has gone through BS with a mechanic to repair the "valves". Of course, the valves never get repaired because that's not the problem. Eventually they find out that it's the intake and freak out because they've already spent so much on it. The car ends up for sale cheap. Find one of those, and you'll be set. Honestly, I can't tell you which tumble flaps will cause a no-run situation, and which won't. I can tell you that the tumble flap is too big to fit through the valve so it won't get sucked into the engine. I've never heard of one falling off anyway. There has only been one instance on this forum where bad tumble flaps caused a no-run problem where the intake manifold was cracked.
I think it's a just a good way to talk someone down on price.
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Originally Posted by the user formerly known as ZX3_Chick
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