Does anyone know if it is a common problem for the intake to breakoff at one of the bolt stud holes? Fortunately I was able to get a good one out of a wrecking yard. There is a bracket that supported the left side of the intake (engine is a 5.0L EFI 85 F250) mine was missing this bracket. I was also able to get this brace at the wrecking yard. I suppose that if this brace is not in place to support the upper part of the intake a lot of stress is transferred to the support bolts. I suspect I have been lean on one cylinder and this may have been a factor to the engine at idle would vary from 700 rpm to 900 all the time. Any input on this subject would be helpful. Richard

 

Was it by chance running lean because of the crack in the manifold, if it protruded to the interior volume of it, or was it some other reason, like a bad fuel injector?

I know the setup you have, as I also have the '85 EFI 5.0 engine, but in my searching on this forum I've not run across your failure yet. Let's hope it was a freak occurrence.

 

Yes let us hope this is number one. I suspect that the bolts also, may have not been tightened with a torque wrench. You know some mechanics don't know there own strength. And yes there could have been a small path to that first cylinder feed by that port. No way to be absolutely sure. I am replacing all the injectors and this is what caused me to notice this piece broken. Doing the upgrade on the injectors getting away from the single nozzle. Richard

 

I just finished this job yesterday. What a P.I.T.A. it was to clean the old gasket off the manifold! I also succeeded in dropping a bolt down the intake because I was trying to rush...I got it out with a magnetic pick-up tool from the nearest parts store. My heart was pounding for a while at the thought of not being able to get it out. I also swapped out the single port to the four port injector. I have no idea if I notice a difference yet, as I didn't finish until late last night, and now the truck runs like crap for some unknown reason. I just parked it and will return to it next week as I started my work week today.

 

What a bummer dropping a bolt like that! It would have ruined my day too. Well I just replaced my injectors with the 4 port vs the single port. My engine was running smooth it just did not want to start if it got hot. Injectors were leaking down on it. Then my horror story started. I pulled a rocker cover and it was gunk city. Have spent all day cleaning the mess up. I have all the push rod holes plugged with wooden dowel's. And as my luck would have it, my air nozzle with siphon tube won't siphon gasoline out of the can to wash it down. So I have to run and buy a new one hopefully it will work!

So your engine is not running smooth after the change out of injector's. Do you have any idea what the problem is. Maybe something as simple as a vacuum leak. Oh my intake was not sucking air where it had cracked. I don't know what was keeping it from it, but the gasket was intact and holding up. Well its off to the parts store... Keep me posted as to your progress on the latent problem. Richard

 

I don't have any immediate idea why it isn't running very well. It stumbled as I started it for the first time, but then ran fine for about a 30 seconds or so in it's fast idle cold start. I shut it down, cleaned up, and when I restarted it I noticed it ran pretty crappy. As it was almost 10 PM and I had to get up for work the next day at 5AM I didn't really care as long as I could move it out of the way. I live in an apartment, so I have to borrow the garage at my mother's place. She would not have been happy if I left my truck stranded in her garage

I changed out a couple other things while I was at it. I swapped out the EGR valve and sensor, and the air charge sensor. Strangely, I found what looked like heavy-weight grease packed into the upper manifold passage that the EGR is supposed to channel exhaust gasses to, yet the EGR valve and pipe were clear. The EGR gasket looked to have been recently replaced, so I wonder if it's possible that the previous owner packed that cavity to mask some problem with the EGR system on this truck? It may have been 'locked out' on the cold start, but then made active after it warmed up a bit. I know there are ways of testing it with a vacuum gauge and a meter, so I will when I have an opportunity.

As for your sludge problem, have you tried a shop vac to literally suck the gunk up? You can first place a bit of absorbent in the collection bin, then suck up the muck. You can actually lead an air nozzle ahead of the vac to blast the stuff right into the nozzle of the vacuum. I did that once, and it worked pretty well at the time.