hey .. i am cleaning my manifold up to reinstall and there is butterfly valves in the manifold(lowerone) the ones on the right side are stuck CLOSED??? what probs would this cause?????? thanks I put some penitration lube on them and leting them soak now..
Andrew

 

I have heard that some of the Ford engines have turbulance vanes that tumble the air to improve the combustion at low throttle settings. The vanes open at higher throttle settings. Could be the 4.2 has this, what year do you have?

 

Those are IMRC's (Intake Manifold Runner Controls). There are 2 intake ports per cylinder, there should only be one of those IMRC's per cylinder (so only half of the runners have them). If you notice on your upper intake you have a long runner and a short runner. Short runner's are good for high RPM horsepower and long runners are good for low RPM torque. The IMRC's close off the short runner during low RPMs to help promote torque, at higher RPMs they open up. I believe they are controlled by vacuum

And I'm pretty sure that all 97+ 4.2's have them

 

yup that its pretty well exactly how it is... vaccum controled.. right side was stuck solid.. took a bit to free them up.. working perfect now.. hopefully makes engine work little better.... thanks.

 

must be a common problem....what is the easiest way to get access to them so I can check mine...or is there an easy way.

 

MJ,you have to pull the upper intake to get access to the runners. Thats where a good de-carbonizing comes into play. I'm going to buy some Amsoil foam cleaner. I'll then remove my TB and spray it into the opening and fill up the upper intake with foam and let it do its thing. My neighbor used it on his Chevy and his runs like a new one. I'll probably do it within the next 2 weeks. I hope it works.

 

are there any alternatives to Amsoil...I dont have a napa or anything like that near me...so stuff like seafoam, and the like are tough for me to get. I got Pep Boys and Advanced Auto...they seem to carry similar stuff but those guys working there dont know what I am looking for when I ask for alternatives to what you guys tell me on here...I am gonna start going online more

Also I have never messed with the TB before...do you just remove the air intake where it goes into the TB and spray it in there?

 

MJ, go to www.SeaFoamsales.com and find out how to order it direct. Or,look in your yellow pages and call oil distributors in your area and see if they can help you out.
About the TB, you can leave it on,but this time i'm going to remove mine and use the Amsoil foam to fill up the intake. Its suppose to cling to the sides of the intake and eat away the carbon build up. As it eats away it turns to a liquid and goes down to the lower intake. I am also going to pull the plugs and turn the motor over to ensure I dont hydro-lock it. Then,i'll change the oil. This is how my neighbor did his.