1995 5.0 5-speed. Started running rough - losing power. Changed the plugs, wires, distributor cap and rotor. Checked the timing, and it was okay (about 12 BTDC). Seemed to help for a day or so, but started running rough again. Pulled the codes and got 332 and 212. I removed the EGR valve and cleaned it - it seemed stuck. That removed the 332 code. Still runs rough as ever, and still throwing 212 - even though the CEL is not on anymore. (I cleared the codes twice and 212 came right back.) I checked the SPOUT for continuity - all okay there. Nothing obvious that I can see, like vacuum leaks or bad wiring insulation.
What should I check next? It will barely maintain 30mph in 4th gear.
Thanks in advance for any and all suggestions.

 

The code 212 most of the time means somebody put on a GRAY ICM where your truck takes a BLACK one.
Check its color but that may not fix all of the running problems.

 

Thanks. Yes - it was gray. I had changed it a couple of years ago (don't drive the truck that much anymore). Luckily, I had saved the old one, and swapped them back. Cleared up the 212 code, but hasn't noticeably improved the missing and loss of power.
It also has a cracked exhaust manifold. Could that cause it to run bad?

 

Yes, cracked manifold will allow unmetered air to flow downstream and give errorneous readings to the O2 sensor.

 

Okay - thanks again. I guess I will replace the manifold next. I've been putting it off because I expect to break at least one bolt off.

 

It's been a couple of weeks, but I only get to work on the truck on weekends between everything else. Upon closer inspection, the manifold was not only cracked, but exhaust was blowing by at the second port from the front. I'd say it had blown a gasket there, but there was no gasket on the manifold. I pulled the manifold and, of course, broke three studs. I had soaked it with PB, and tried to carefully work them back and forth, but still broke them. Got lucky on one and had enough sticking out to get a small pipe wrench on it and removed that one. Drilled the second one (last stud in the back) and successfully removed it with an Easy Out. Third one was not so easy - broke the Easy Out off in the bolt, flush with the surface. Didn't take much force at all to break it.
So - I think I've about done all the damage I can do working upside down on my head and using a mirror and light to see what I'm doing, so next I plan to remove enough of the inner fender so that I can get a straight shot at the bolt. The Easy Out wasn't that tight, so I think my first plan will be to try cutting a slot in it and backing it out with a screw driver. May not work, but I figure to try the easiest trick first. I'll have to wait until I can get a cut-off wheel for my dremel that might cut the Easy Out.
Oh, and I took the manifold to the local welding shop and had them fix the manifold. They ground a groove in the crack, which was about 3/4 of the way around, and used what he called "cast iron rods" to patch it. Looks good and cost $8. Now - if I can just get that last bolt out...