The net effect of removing the EGR, whether OBDI or OBDII equipped is that the fuel mixture will run leaner, absent some other alteration to fuel supply programming. The EGR routes exhaust gas back into the intake to dilute the amount of oxygen in the fuel mixture, lowering combustion temperatures and thus NOx readings.
The lean burn situation will trigger a CEL, as will the lack of any feedback to the on board computer from the missing EGR system.
If you live in an emissions testing jurisdiction, your OBD I truck, 95 or older, may pass the sniff test--it will be at worst a 2 speed idle test since nobody uses a 4 wheel dyno, and our trucks are full time 4wd. That test does not put a load on the truck engine, and the head temps may remain low enough to pass even with the disabled EGR. On an OBDII 96+ truck, unless the on board diagnostic computer can be made to think that the EGR is working as designed (there exists an electronic gizmo that makes the computer think that a catalytic convertor is mounted, when if fact it is missing), a fault code will be thrown and the truck will not pass its annual emission test. One additional tactic to make the truck run richer (and therefore cooler) for an OBDI inspection is to retard the ignition timing. Too much retardation will result in HC and CO being too high though--it is a balancing act.
I must add that monkeying with the factory installed emissions control systems is severely frowned on by state and federal environmental folks.
Some vehicles (prolly not LandCruisers) come both with and without EGR's based upon where they were originally sold--old Saab 900's for one example.
