need help re: intake manifold

[68GEETEE]

I have a '96 GT 4.6 with 104k miles. Coolant was leaking from a crack at the manifold water neck into the number 3 and 4 spark plug housing. The engine was missing real bad and the check engine light blinked. Scanner said #3 cylinder missing. SO today we installed a good used manifold, and the engine is still missing. Pulled the #3 plug, it was covered in coolant. Replaced it. Pulled the #4 plug, the electrode is worn to a nub. Replaced it. Engine is still missing, however now the check engine light is off. I didnt check the other plugs yet. What could we have done wrong, if anything? Can torquing down the intake manifold bolts too tight or loose cause the engine to miss?? Need help please,

Dave

P.S. miss is most noticeable under a load, accelerating, going up a hill, etc.

 

[Screwed2V]

If you had two bad plugs I would suspect that you may have more.

 

[keepsbreakin]

I would suggest changing all plugs anyway when doing the intake. Did you get one with the aluminum cross over like the police Crown Vics of that era? Change the wires as well. I just had the same problem on a 4.6 truck. New intake, but still had misfire in #4. We replaced all plugs, wires, and the two coils (cheapo ones) it ran fine, no misses.

 

[68GEETEE]

unfortunately I replaced it with the same type of manifold that was on there, good ol plastic. The wires look to be original. I bet the other plugs are just as worn as the ones I replaced today. Just not sure that new wires and plugs are the only reason its acting like this. anyone else have anything they can suggest?

 

[68GEETEE]

anyone else have anything to add to this?

 

[Bone Racing]

classic 96-98 intake break sounds like to me

ford screwed up...most people have gotten then warrantied for free...even if your warranty is UP, cause it was a silent recall

gives u a chance to do the PI swap

 

[Dan_Soprano]

check the other plugs, maybe the wires and coil packs also..........if all else fails, might want to check the oil for signs of anti freeze in it. If there is, you might as well do the PI headswap cause your going to be pulling the heads off anyway to change your blown head gasket!

 

[68GEETEE]

no oil in the engine, and they wont warranty mine, said the recall expired on mine 10 months ago

 

[68GEETEE]

could the intake have an air leak after we installed it? It went on pretty easy, I dont see what we could have done wrong

 

[68GEETEE]

***UPDATE***

Installed new plugs and wires, she runs great now!!! Just one problem, the check engine light is on and the code that comes up is P1443, some sort of emission code. Can anyone here tell me what part I need to change to get that light off? THanks,

Dave