TCC solenoid

I have a 95 Chevrolet cavalier. 2.2 4 cyl auto. It's been stalling when I come to a stop after driving for 20 to 30 minutes. I had hesitation /loss of power issues as well as difficulty with cold start ups. I've had the fuel pump/fuel filter, the battery, the ignition control module changed. I even unplugged the TCC solenoid the way many have suggested. The hesitation/loss of power issues and difficulty with cold start ups disappeared. For a couple of weeks I was even able to drive it for more than 30 minutes without it stalling. But then the stalling came back at stops after 20 minutes of driving. The check battery and check oil lights came on at the time of the stall. Someone told to me to put fuel injector cleaner in and I test drove the car for 45 minutes with no problems. But after parking for a minute and starting the car again the check engine light came back on after 3 minutes of driving. Do I need to simply have the TCC solenoid replaced or is the check engine light coming on a side effect of unplugging the tcc solenoid? I had the car scanned more than once but no codes came up. I've taken the car to more than one mechanic but no solutions. Thanks for any help you can give me.