I've got a 91 civic hatch in the shop. The MIL is on and it shows four codes, Injectors, EAC, TPS, and IAT. Once the light comes on the car goes into some kind of limp mode where it won't allow you to exceed 3500 RPM's.

All of these sensors are on the same harness, goes to a round connector at rear LH side of engine compartment. I inspected the major round connector, no corrosion or loose pins. Unfortunatly I don't have a pinouts on that round connector so I can't check that segment of the harness.

The plugs on 3 of those individual sensors are identical but the correct plug is on each one, checked that against a wiring diagram.

This one is got me stumped, any help on this would be appriciated.

Thanks,
Russell