88 accord lxi intermittent crank no start. I haven't verified yet why but is the main relay a culprit these years?

By cranking, you mean the engine does not always spin when you turn the key, correct? Main relay would not be the problem unless the engine turns but will not start. Your problem could be battery and/or connections to the battery, ignition switch, safe switches ie. clutch switch on manual, park/neutral switch on automatics or starter.

"Crank No start" meaning the engine cranks via the starter motor but will not run.

OK, now I understand. You should have said always cranks but intermittent start. Could be the main relay but could also be the coil and/or igniter. It is located on the left side of the dash on the kickpanel under the dash. It is a bitch to get to because it is above the first module you see when you look up there. The problem with the main relay usually is cold solder joints on the relays that connect to the PC board. You can fix that yourself. I would do a igniter test first. If you pass that, the igniter is OK and so is the pulsing circuit of the ECU and also the main relay. If the igniter test passes, look to the ignition coil. Sometimes they can be intermittant.

I had the same problem on mine about 5 years ago...took forever for us to figure out it was a rotor switch...20 bucks to fix at the dealer back then...