My 92 with about 50,000 miles started experiencing cold start problem. I replaced the 4 pin coolant temperature sensor and at the same time noticed that the electric connection to the "Upshift Relay Switchover Valve" was not plugged in. Pugged it in. Engine started much better, but still stumbled a bit on idle for a minute or so. Now the tranny would not upshift for serval blocks of driving in 1st gear. At first I thought the new temperature switch was controlling the up shift. Also experienced a problem with the kick down to accelerate. Today I unplugged the URSV and shifting returned to normal. Both upshift and kick down. I tested the URSV the solenoid clicks with power and the valve ports change connection with the power, so I believe the valve is OK. Am I causing some other problem by not having the valve connected? I bought this 300 with 34,000 miles two years ago. It was always serviced on a regular basis at an indy shop. I assume the shop had disconnected the valve. Any thoughts or am I just concerned about nothing?