Hot_rod_lincoln_1970 said:
Laugh if you may But the auto zone guy is right. I have the same issue and its the actuator that operates this "flap" and you will have to remove the intake to repair, according to alldata its a 4 hour job. I have had luck with clearing the code and it stays gone for awhile till i let the car sit for more than a week and its comes right back. This leads me to belive its a sticking issue (dirt) around this flap not the actual actuator. The last time it came on it cleared itself, but then i drove my mark yesterday and it rough idled and the damm light is on again, car drives fine now but now i have to clear the code.
Have you ever seen the 4.6 4V '93-'96 intake manifold taken apart? I am pretty sure we have some pics of one here on the site if you do a search. If not, I could take a pic of one I guess. (lazy)
Essentially, you have a 1/8" diameter rod running thru the manifold on each cylinder bank directly perpendicular to the intake air path. The 4.6 4V intake has 16 runners feeding air to the engine. The engine has only 8 injectors feeding gas to 8 cylinders.
When driving around under 3200 rpm, the 'flaps' stay closed on 8 of the runners. Above 3200 rpm, the 'flappers' rotate 90 degrees to allow air into all 16 runners feeding the 8 cylinders. As stated before, if all 16 runners were open all the time, there would not be enough air velocity to 'fill' the cylinders, resulting in less torque from the engine. So Ford came up with the IMRC (Intake Manifold Runner Control) concept to aid in low speed engine torque production as well as provide high speed rpm and hp production.
The system works great but where Ford screwed up was in the exhaust design and volume. The engine inhales with little congestion. Exhaling is a different story. You can add a blower and such but without reworking the exhaust ports and manifold, you stand a much greater chance of burning the pistons. Too much in, not enough out. That is why our motors love headers and exhaust. They also love head work, especially on the exhaust side.
Long story short, if you knew what the IMRC 'flappers' looked like, you would have a better idea understanding how carbon buildup might potentially make them stick in either the open or closed position. After all, they are vacuum operated so any buildup on the bar and brass bearings will tend to bind a little bit.
I would recommend investing the time and hassle of a couple cans of Seafoam (Pepboys, AutoZone etc.) or try Berrymans B-12 Chemtool (Walmart, Advanced Auto, etc) or even Marvel will do pretty much the same thing as the Seafoam. I prefer the Berrymans (cheaper than Seafoam, works as good) and I'm in Walmart more often.
