OK, here we go...
Saw this question when I was searching the net to see if the '88 Bird/LX was still alive out there. Saw two Turbos driving over the Outerbridge a couple of months ago and it brought back memories. I owned one, metallic blue, loaded, bought it brand new back in the day. The best car that anyone could own and even when the FORD paint peeled and everyone nicknamed it the "Road Warrior" it performed at its best. Put 213,000 on the vehicle and you can bet I have the best mechanic in the world.
His reply, "Usually, the O2 sensor is located in the exhaust manifold. There is a possibility that there may be as many as 4 sensors in that car."