HondaCivicForum.com - 95 civic loses power when warm

My friend Debbie has a 1995 Civic D15 that starts from cold just fine and runs good
until it starts warming up.. About the time the temp gauge gets off the peg it starts
to run rough and lose power. It gets worse as it warms up. At some point it turns
on the check engine light and seems to smooth out a little, but not enough to make
it drivable. By the time it gets to normal temp it won't even pull itself and
sometimes the engine dies.

I've turned a lot of wrenches over the years, but I'm no Honda guy, and I really
need to help her out. I'm hoping you Honda gurus can point me in the right
direction.

Here is some more background, as I understand it. Somebody replaced the head a
few months ago. I'm not sure why. It ran fine but leaked oil like crazy. Apparently
the new head arrived with the camshaft seal MIA. I installed a seal and ran the
rack.

It ran good for a week or so and then a "cloud of steam or smoke" came out from
under the hood. She shut it down and towed home. I found a leaking heater hose,
cut it back a little and reclamped. No evidence of overheating.

It ran fine for a few days and then she complained about a lack of power. I found
the muffler was plugged tight (cat converter was clear). I replaced the muffler and
it straightened out for awhile.

Then the current symptoms developed. It will go through the cycle of warm up and
fail in just a few minutes while idling in the driveway. It's OBD1, and has never
shown a blink code. While troubleshooting the plugged muffler I checked the valve
lash adjustments and all were on the money, but now it seems a little loud to me.
It's a clattery, metalic kind of noise like loose valves.

I think that's it. I'm sorry, at this point I can't even tell you if it is a fuel or ignition
problem. Haven't had the heart to run it down yet Please help. I'm starting to
really hate this thing.