1995 chry cirrus - limp mode - SO

Greetings: I own a 95 cirrus that has had the following work. Air filter, fuel filter, plugs changed (V6 2.5L). Timing belt, water pump, intake gaskets, valve cover gaskets,replaced thermostat, replaced oil sending unit, flushed cooling system, and changed trannie, (yes the ATF+4 was used). My son's car. Now when the weather gets hot, (he doesn't use the AC - windows down) the temp gauge climbs, the brake light flickers and other dash lights may flicker, you can be assured the car will go into limp mode. Some times you can pull over and wait a few minutes to cool down, it may be okay to drive for the next 500 miles. The last time, he had to limp home. I had it scanned and the code came up as 2&3 solenoid circuit problem, - replaced the solenoid pack on transmission. Now the last time, the code came up 42 - and I was told it may be a broken wire or ground. The three ground wires were traced but all are secure, intact, and not frayed. Any more ideas??? I am running out. Thanks.