FYI, on mid 90s accords, if the light comes on and then goes back out, it stores the code, so you can still check it by jumnping the blue plug underneath the dash on the passenger side..
both of your cars sound like VTEC issues.. whenever the VTEC system is acting up, it will start to limit the revs when it goes to hit VTEC if something is not in check.. did you try a new pressure switch or just some other old ratty pressure sensor? have you checked oil pressure? the oil pressure can be low enough to affect VTEC yet not be low enough to turn on the low oil pressure light.. check that, and if the oil pressure is fine, check for continuty between the ECU pins that correspond with the wires at the pressure solenoid... could be a burnt/broken wire, or a loose connection on the harness or at the ECU.