I would think that the MAP & CTS would throw a code if they were faulty. As far as the HEI module, usually when they go bad, they're done. Not usually an inconsistant issue.

I personally would take the cap & rotor down to the local NAPA store & have them match them up for you. I have used the following #'s on a Hyster with the V-6: RR203 cap, RR173 rotor, 700322 wire set & AC plugs- R44TS. The cap is fairly large (probably about 6" in diameter)- if you have a small cap (about 4" in diameter), the cap & rotor #'s are incorrect for your application

I've always had great luck with NAPA igntion parts. Usually the dealers sell aftermarket ignition parts which have always been a headache for me. Hope that helps.