On Wed, 25 Jul 2007 09:53:04 -0700, john wrote:
Snipped
John Many people leave the engine running when they wash it. The
5.0 & 5.8 engines used a two piece intake manifold. Many of them experienced failure of the gasket between the upper and lower sections of the intake. If the engine was running when he wet it, it probably sucked some water thru the bad place in the gasket making it seal a bit better momentarily changing the the way the engine was idling. Replacing the gasket usually fixes that problem. I thought we had mentioned that as part of the check for vacuum leaks earlier in your problem - maybe it was another thread. You can check this gasket for bad leaks with a can of carburetor cleaner or even WD40. Don't use starting fluid (ether) for this. If that is the problem, it is a cheap straight forward repair to remove the upper intake, clean the gasket surface and replace the gasket using a very thin coat of sensor safe silicone sealer like the Permatex Black or Gray. You should be able to do this job in under an hour even with OJT. Allow it to set up for about 10 minutes before installing the upper intake. Also, if you do this, make sure you do not pinch the small plastic vacuum tubes that pass by the back of the manifold. That is very easy to do. IIRC, the 5.8L also has a torx head bolt in the middle like the 5.0L. I don't recall the size but, you will need to use a long 1/4" drive extension to reach it from the top. It is much less frustrating if you use electrical tape and firmly attach the bit and socket to the extension unless you have very small hands to fish it from under the manifold. If you get an upper intake gasket kit, it will have a throttle body gasket so you can disconnect it and push it forward out of the way. You don't have t worry about losing any coolant from the intake as it is dry. You must use a good accurate torque wrench to install the bolts or you will cause a bigger problem than you are fixing. You may be able to borrow one that will work accurately in the 250"/lb range. I do not recall the exact setting for those bolts. You will need metric tools and a way to adapt your sockets for the torque wrench to 1/4" drive unless you come up with a good 1/4" drive torque wrench.I hope I have written this such that it is understandable. It has been a long time since I was intimate with this exact engine. I believe Tom who has responded above is still an everyday Ford tech with about a hundred years experience. His answers are usually dead on on the Fords given enough info.
Good luck
Lugnut