Your car doesnt go into limp mode because they are the rear O2's. So with MIL's you are just getting rid of the light on the dash. Tho when I bought MIL's after a couple days driving the light would still come on and I would have to reset computer. I fixed it with the Diablosport Predator. It allowed me to turn off the rear O2's.
Only vehicles equiped with OBDII (96-up) require MIL eliminators because they have O2 sensors after the cats. Most likely the cause of your 88's check engine light is a bad primary O2 sensor.