Chrysler Repair: 1994 3.0L missing when warm, coolant temp, rich mixture

Question
QUESTION: my 3.0L  (100k) runs rough(er) the hotter it gets or longer you drive it, you can feel random missing at idle.  I have another one so these parts are free - changed ecm, tcm, wires, plugs, distributor, cleaned egr.  Didn't change any injectors, crank or o2 sensor; didn't know if this would cause a miss
when hot.  Any ideas?    Thank you

ANSWER: Hi Doug,
Get the fault codes using the ignition key. "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to see it begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat to assure an accurate set of flash counts. Then group the counts in pairs in the order of appearance. Those are the fault codes.
Go to www.allpar.com/fix/codes.html for a code list. Write back if you have questions.
Roland

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QUESTION: no fault codes, even went to a friend with a mtg2500 scanner to reset and look.

Answer
Hi Doug,
I assume that at least you got a code 55, if not then there is something wrong with the pcm.
The more likely issue is a failing crank or cam sensor. The crank is much less expensive if you are going to 'throw parts' at it. The cam is part of the distributor and isn't sold separately so that is a bit too much to guess about. The coolant temp sensor may be off value, it should read around 700-1000 ohms when the system is up to temperature. If it reads higher than that I would replace it as that would cause a too rich mixture/miss. The sensors being solid state means that when they are wearing out they begin to miss when heated. So any of those three could be the issue.
Roland