CEL code 34 after warm up

[joeaxial]

I've been trying to get my 1992's CEL to quit coding a 34 for several months. 34 is the code for a bad EGR solenoid valve. I replaced that part when I had the intake off to replace the rubber lines that lurk beneath. I thought for sure this would take care of the problem, but no! the CEL comes on upon warm up after each and every cold start. It usually comes on just after the climate control starts ramping up the speed of the heater fan. One other oddity is that the engine temperature gauge in the dash does not work, its always about 1/3 of the way up from cold. Could this be a bad sensor which could also by causing the engine computer to throw a code 34?

Other than the CEL the car runs perfectly, no hickups at all!
Steve