This is causing my FF39, not the one I had changed out.

The one outside the engine compartment is one I pulled off a 94 today.
The one inside the engine compartment is on my car. Changing it out is a PITA, no room under the sensor to fit a socket, nor wrench.

 

EGR solenoid. It's a pretty standard vacuum solenoid, also used toward the front of the engine for some other system I cannot remember offhand. There is no nut on the underside of the bolt securing it to the bracket, so you should be able to remove it fairly simply with an extended socket. It is easier to unplug (take the little wire retainer off carefully or you'll lose in!) once unattached from the bracket.
Scott

 

By the way, just looked at your picture of the dueling XJ40s in the garage. Pretty sweet!

 

Thanks, now I want a white one...

The EGR sol is attached to the motor on the 90. The 94 has the set up you explained. I'll show you a close up tomorrow.