Found vacuum leak. What to replace?

[blacklimited07]

I've been having more misfires on my V8. Vehicle running rough shaking. Codes pulled were P0316(misfire startup), P0308(misfire cylinder 8), P0714 (lean bank 2).
Swapped injector from cyl #8 to cyl #7 and misfire followed.
Made a DIY injector cleaner and cleaned all 4 on bank 2. Success spray patterns went from looking like a hose to a mist. The problem injector was clogged and not pulsing half the time.
Cleared codes P0316, P0308 went away. Misfire count now at 0. P0714 came back though. Making progress..
Long term fuel trim very high at the maximum 25%.

Sprayed some soapy water around at the backside of manifold on bank 2 and can hear hissing.

Should I replace the Intake manifold gasket? I saw in another post a guy with a vacuum leak in the same area but his was the runners.
This is his video:


Another thing I noticed my Fuel % PID in the Torque app is a bit erratic. Sometimes dropping to 0. I caught it happening in the first imgur link that I posted. What could that be caused by?

 

[blacklimited07]

Another video of where the leak is:

Should I go ahead and do the manifold gaskets?

 

[DblCircles]

Let me just say it seems like you have a slightly more severe version of the same problem I have. I have a 2006 with the V8 with about 220k and over the past year or so my gas mileage tanked so I decided to change my manifold gaskets the lower set that is. It fixed it for a little while where I managed to get 20mpg highway on a 600 mile trip, but then it dropped again after winter time. I've had the manifold off 3 total times and the third time I took the manifold runners off the intake and cleaned the surface and applied fuel safety gasket maker around each gasket and re assembled the runners back on. After doing that I still had doo doo mileage and sprayed around the manifold. It seems with age the plastic bushing that actuator rod goes through the runners is degraded. Only downside is the runners cant be removed without breaking stuff. It seems to be letting a lot of air at the rear cylinder causing lean conditions. I've got a spare intake by me I can grab some pictures to show you how this wonderful designed piece looks, but I get around 10 mpg city now with average of +5 to +7% short term trims on both banks and LTFT hover around +9% as well. Sucks gas money away but I still love driving it.

 

[DblCircles]

These first two photos are the mounting surfaces. The grooved side are the gaskets you buy from the auto store and can replace. The smooth side has gaskets that go in the upper intake and mate the runner. This smooth side is where I applied sealer to help fill in holes as the upper gaskets are not a part number by Ford nor are they even available unless you get a whole new intake assembly or junkyard like I did.

These pictures are where I am currently experiencing a vacuum leak and haven't done much to fix it. I have tried seeing how they come apart but they seem to be riveted or fit during assembly. I have though about taking my intake off again and seeing if filling the slot with sealer and working it into the bushing may work but it would require extensive dry times to make sure it doesnt seep or get into spots it shouldn't so I have just lived with crappy gas mileage unfortunately

 

[blacklimited07]

These first two photos are the mounting surfaces. The grooved side are the gaskets you buy from the auto store and can replace. The smooth side has gaskets that go in the upper intake and mate the runner. This smooth side is where I applied sealer to help fill in holes as the upper gaskets are not a part number by Ford nor are they even available unless you get a whole new intake assembly or junkyard like I did.


These pictures are where I am currently experiencing a vacuum leak and haven't done much to fix it. I have tried seeing how they come apart but they seem to be riveted or fit during assembly. I have though about taking my intake off again and seeing if filling the slot with sealer and working it into the bushing may work but it would require extensive dry times to make sure it doesnt seep or get into spots it shouldn't so I have just lived with crappy gas mileage unfortunately

Thanks for the pictures. That really sucks. Apparently the manifold has been revised from Ford as what this guy said on that youtube video.
@ScottKelly3
"I bought a whole new OEM intake manifold from Tasca Ford. Ford completely redesigned the intake manifold to remove the metal intake runners that were leaking. Ford obviously discovered they were a problem. The new intake manifold has the runners integrated as one part. At one point I tried to purchase replacement runners on Ebay but kept getting damaged ones. Finally just replaced the whole intake. Heads up, if you replace the manifold the original bolts are too long, you'll need to either cut the existing bolts or purchase the new correct length ones."

I didn't have much luck finding a new manifold online but didn't really look to hard just the usual places rockauto, amazon. Will try the dealership for a quote next.
The other option would be try and plug the leak with something like petroleum jelly but not sure how well that would work. or maybe some type of flexible sealant.

 

[94Eddie]

Thanks for the pictures. That really sucks. Apparently the manifold has been revised from Ford as what this guy said on that youtube video.
@ScottKelly3
"I bought a whole new OEM intake manifold from Tasca Ford. Ford completely redesigned the intake manifold to remove the metal intake runners that were leaking. Ford obviously discovered they were a problem. The new intake manifold has the runners integrated as one part. At one point I tried to purchase replacement runners on Ebay but kept getting damaged ones. Finally just replaced the whole intake. Heads up, if you replace the manifold the original bolts are too long, you'll need to either cut the existing bolts or purchase the new correct length ones."

I didn't have much luck finding a new manifold online but didn't really look to hard just the usual places rockauto, amazon. Will try the dealership for a quote next.
The other option would be try and plug the leak with something like petroleum jelly but not sure how well that would work. or maybe some type of flexible sealant.

Did Ford revise the manifold after production of the 4.6L 3V ended or during production? If it was during production, what year did this happen?

 

[DblCircles]

Did Ford revise the manifold after production of the 4.6L 3V ended or during production? If it was during production, what year did this happen?

It appears 2009 had a redesign to a full plastic assembly, but it has a different gasket design, not sure about mounting if the bolt pattern matches to the older design from pre 2008. I believe he means this part.

 

[94Eddie]

It appears 2009 had a redesign to a full plastic assembly, but it has a different gasket design, not sure about mounting if the bolt pattern matches to the older design from pre 2008. I believe he means this part.

Thanks for the info. Sounds like I might have dodged a potential problem since I have a 2010 model.

 

[blacklimited07]

View attachment 451202

Is that a bearing or bushing where the arrow is pointing to?

I have some Lucas red and tacky grease on hand. I'm honestly ready to just try and pack some of it in and around that pivot point and hope for the best.

 

[DblCircles]

Is that a bearing or bushing where the arrow is pointing to?

I have some Lucas red and tacky grease on hand. I'm honestly ready to just try and pack some of it in and around that pivot point and hope for the best.

View attachment 451237

Can't say for sure what it's made out of but it is a bushing. Knowing Ford its probably some plastic but could also be a bronze pored bushing pressed into the runner. I don't think red and tacky would do much to help as if it's pulling vacuum it'll slowly bring grease into the intake. I would start personally replacing intake gaskets and if you feel comfortable disassembling the intake runner you can clean and seal the uppers with proper gasket maker. I've thought of using sealer on the runner rod but I don't want the runner to sieze and get stuck which will cause more problems instead of good

 

[blacklimited07]

Can't say for sure what it's made out of but it is a bushing. Knowing Ford its probably some plastic but could also be a bronze pored bushing pressed into the runner. I don't think red and tacky would do much to help as if it's pulling vacuum it'll slowly bring grease into the intake. I would start personally replacing intake gaskets and if you feel comfortable disassembling the intake runner you can clean and seal the uppers with proper gasket maker. I've thought of using sealer on the runner rod but I don't want the runner to sieze and get stuck which will cause more problems instead of good

Alright I think I'm going to hold off on the intake gaskets for now as I am pretty sure I figured out my issue.

As I mentioned in my first post I had an injector that wasn't pulsing very well. I thought the cleaning had cleared it up at which it did but I'm thinking now it is just bad. Some new o-rings that I had ordered came in today for them. So after finishing the cleaning on bank 1 I decided to swap them with bank 2 (my problem bank with the high LTFT).

After clearing the KAM memory and watching my fuel trims, bank 1 is now high which tells me one of the injector is definitely at fault. I also got a code for P0171 (bank 1 lean) instead of P0171 (bank 2 lean). I have a new Motocraft injector ordered which should be here tomorrow.

I was doing some research on that leak at the back of the runners and I think I read something about it being normal for a leak there.

Anyways just thought I would give an update.