Rough idle, stalls, lack of acceleration up to 3000 RPM. Replaced ignition parts, same result. Performed a compression test and found cylinder #3 has about 50lbs of compression, other cylinders have 80 to 90lbs. Appears I have a valve or ring problem. Is this common with this vehicle or did I just get lucky?

 

It sounds like you may have either jumped timing or have a blown head gasket. Do you have a way to check your timing? Also, check for low coolant, coolant in the oil, oil in the coolant, or have someone rev up your car while your watching the coolant and see if it has bubbles in it. The bubbles could be a sign of exhaust pressure getting in the coolant (sign of blown head gasket)

 

IF the timing jumped they would ALL be off /low ...
Likely the valves may have build up and not seating/sealing right especially if the car had had regular fuel run thru it....

 

Bentley manual shows a range of 131Lbs to 196 Lbs. So, they are all low. I saw this a lot in the 1G eclipse/talon world. I would assume the car jumped timing and maybe has a bad spot in the head gasket on that cylinder, or the valves may have kissed the piston. Just my opinion, but I've been a mechanic for almost 11 years now, professionally for 6.

You could conduct a leak down test to see where the compression is escaping too. You'll need an air compressor and a few common tools to make the tester though. Just go to google and search for "leak down test" to find several different options.