check engine

Hello everyone. After finding a burned spark plug wire I had a full tune up done and now when I drive long distances on the highway and come to a stop the check engine light comes on or if i'm just driving in the city it will come on like 10 minutes after i start driving. I'm getting 3 different codes. 15, 23 & 32 in situations like this I never know if they are related or where to begin to solve the problem. Before the tune up I would occasionally get a 15 or a 32 but not everytime I would run the car.

89 caprice tbi w/350 from an early 90s van
straight dual exhaust w/o cats

Code 15 and 32 are coolant temp sensor and EGR valve respectively. A code 23 on a TBI would be inlet air temperature sensor displaying an invalid temp, i.e. -22 degrees F for 5 minutes after engine started.

Check all of your sensors and connectors, as well as the general condition of the wiring harness.