fenza89

06 fx4 77,000 miles, i have done new coils, new plugs, new fuel filter, new air filter, cleaned throttle body and MAF sensor. I can't figure out what is causing my truck to run rough, JUST IN PARK... when i put it into drive or reverse it idles fine. when i put it in park, the idle is way to rough to be normal, i can't figure it out to save my life. if anyone has any ideas i would appreciate it. I have no CEL

Summers22

iTrader: (2)

On the throttle body is an IAC, idle air control, it has a plunger on a spring. Give it a good cleaning with a carbon cleaner.

VTX1800N1

There is no IAC on these trucks.

To the OP, I removed my intake, disassembled and completely cleaned the CMCV flaps and it runs much better. Actually got better fuel economy out of it too.

nufan

can you elaborate on this please or IM me on how to do this?

VTX1800N1

Remove the intake snorkel. Disconnect the MAF electrical (pull the red tab toward the driver side and then slide the connector off). Remove the 4 bolts and remove the upper intake. There may be vacuum lines attached or clipped to it. Disconnect the passenger side electrical from the throttle body. Remove the 4 bolts from the throttle body and pull it off the lower intake. Disconnect the driver side electrical from the throttle body. Disconnect the fuel line. You will need a special release tool for this. Disconnect all 8 fuel injector electrical connections. Unbolt the 4 fuel rail bolts and remove the fuel rail and injectors from the lower intake. Fuel will spill out but clips will keep the injectors in the rail. Remove the electrical from the alternator and remove the alternator. There are 6 bolts holding it in. Of course you will have to remove the serpentine belt first. Remove the driver and passenger side PCV tubes and any remaining electrical or vacuum connections to the lower intake.

Remove the lower intake bolts (12, I think). Tilt the front of the lower intake up and reach underneath to disconnect the electrical for both knock sensors and the passenger side cylinder head temperature sensor. Be careful how you tilt it so that the intake doesn't damage the temp sensor wires. Reach all the way under to the back passenger side to disconnect the CMCV motor electrical. Reach all the way back under the driver side of the intake, toward the outer edge, and disconnect the vacuum supply for the brake booster from the lower intake. Pull the lower intake out by carefully tilting it up at the front and guiding it out.

You will need a Torx driver for the rest of the disassembly.

VTX1800N1

There is one metal rod per side the connects the CMCV motor to each flap axle. At the back is a cap with 2 Torx screws. Remove them and remove the cap. You can then disconnect the pivot arm at the axle and pull the axle out of the lower intake toward the rear, leaving the CMCV flaps behind. Remove the Torx screws holding the flap retainer in the intake and carefully pry the retainer out of the intake, bringing the flaps with it. There will probably be a lot of crud built up. It can be hard to see how it comes out. Just be careful. Each flap also comes out of the retainer along with two plastic bearings. Be careful because they are thin metal and easy to bend. You can pry them out with the axle one at a time.

Clean everything thoroughly with carb cleaner and a rag. Carefully inspect the lower intake to cylinder head gaskets for damage. Clean them with carb cleaner. Clean the cylinder head intake surfaces with carb cleaner. I suggest doing one side of the CMCV at a time so you can see how it all goes back together and remember the orientation of the flaps.

VTX1800N1

Reassembly is the reverse of removal. Coat the vacuum nipple on the back driver side with oil to assist getting the vacuum hose for the brake booster back on. That is the hardest part of reassembly. Also put clean motor oil on the fuel injector o rings or they will be damaged when you put them back in the lower intake.

VTX1800N1

Also, don't turn the CMCV motor by hand, you can damage it.