2001 upper engine knocking sound

My '01 with 71K has started to exhibit what I can only describe as a knocking sound around the upper intake area. I really don't notice it when driving, only when the hood is open and I rev it to about 2000rpms, and drops back down to idle it's really noticeable. I can also feel it on the intake plenum. It doesn't sound like an exhaust leak. I'm stumped. Any ideas?

I got a reply from the bobistheoilguy.com board from someone who stated it may be the upper intake baffle that has come loose. So, if that is the case, and if I have to remove the upper intake, I may as well do the port seal and isolator bolt repair too, right?

I would at least inspect the bolts. Remove one of the (8) isolator bolts and see if it has green or black rubber. If green, they have already been updated and you're home free. Remember: only 7 - 8 ftlbs to torque!

OK- I'll pull the cowling and intake later this week and take a look at one of the bolts. It looks like I have the updated LH valve cover (I don't see the small 3/16" hole inside the cover looking through the PCV hole). I'm more concerned about the knocking sound. I'm searching for other threads. Thanks!

EDIT: Yup- I searched (duh) and found a bunch of other posts concerning this. I'll try the RTV fix if indeed the baffle is loose.

I pulled apart the upper intake and yes, the baffle is indeed loose. I can see where the air baffle attaches to the upper part of the intake with clips, but I'm not going to try and fix it. I take it a properly 'functioning' air baffle is not supposed to have any play in it, correct? I also pulled out an isolator bolt and dammit! :banghead: it's a black shouldered one so I'm going to do the fix anyways even though I don't have the 0171/0174 code yet. Seems easy enough- thanks to invaluable info everyone has given on this board!

I pulled apart the upper intake and yes, the baffle is indeed loose. I can see where the air baffle attaches to the upper part of the intake with clips, but I'm not going to try and fix it. I take it a properly 'functioning' air baffle is not supposed to have any play in it, correct? I also pulled out an isolator bolt and dammit! :banghead: it's a black shouldered one so I'm going to do the fix anyways even though I don't have the 0171/0174 code yet. Seems easy enough- thanks to invaluable info everyone has given on this board!
Hey!! Some on here have used RTV silicon around the snap points of the baffle. I did not like this idea myself for fear of some flacking off into the intake stream. So when I did my isolator bolt fix I just got a new upper intake plenum with the updated plastic baffle that is plastic welded to the upper intake plenum. I did it all isolator bolts package of 8 port seals and upper intake plenum for just under 300.00 with the upper intake I think was around 120.00. Cant remember now.I do know the dealer was telling me 600.00 to 1,000 to do what I did for under 300.00 The 1,000 was comming if I needed the upper intake replaced which I did and my egr ports cleaned which were not bad but I cleaned them anyway..If you do it. Go ahead and replace everything in one hit.. Not that hard of a job just pull the cowel off the wipers and all will come with it..Makes it a lot easier. 171-174 problem may never show up on yours after that. hope this helps..OHHH I too have a 2001 and my valve cover was ok as well.. And it was around the 74,000 or 75,000 when mine started giving me trouble..Interesting...

I just scored a new upper intake from ebay for $67 and bought all the isolator bolts, port seals, vacuum line and upper intake gasket from www.1stfordparts.com for $89, so I'm a happy camper :grinyes: . I already have the updated valve cover so I don't need that. I'm a pro at removing the cowling so I think I can do the whole job in under 4 hours if I really go slow. The EGR ports didn't look all that bad when I took photos of them last night, I'll still hose them down with some Deep Creep and I'll probably clean up the butterflies a bit too. It may be all in my head, but the van seems to have a bit more snap with the air baffle removed. I should probably make a cold air intake and really rice it out :pimp: ...

I just scored a new upper intake from ebay for $67 and bought all the isolator bolts, port seals, vacuum line and upper intake gasket from www.1stfordparts.com for $89, so I'm a happy camper :grinyes: . I already have the updated valve cover so I don't need that. I'm a pro at removing the cowling so I think I can do the whole job in under 4 hours if I really go slow. The EGR ports didn't look all that bad when I took photos of them last night, I'll still hose them down with some Deep Creep and I'll probably clean up the butterflies a bit too. It may be all in my head, but the van seems to have a bit more snap with the air baffle removed. I should probably make a cold air intake and really rice it out :pimp: ...
WOW you mean the thing will run with the baffle out.. Really???? And is the upper intake the newer updated one???

.. I should probably make a cold air intake and really rice it out :pimp: ...

There you go. Blow a hole in the fender and run an air snorkel straight up! I hate the 1999-2003 air filter housing. A royal PITA to work with. The 2004+ square filter is much easier to work with. Like we chatted about over at BITOG, that baffle is more for NVH than anything.

Joel

Ahh- so you're JTK on BITOG. I'm really tempted to 'reengineer' air filtration on my van. What a lousy design.

If you disconnect the electric connector and hose ... and then remove the entire air filter canister (including the flex duct on 1999 - 2003) from the vehicle (only one hose clamp remaining at the throttle body) ... the air filter is much easier to deal with once on the work bench.