We have a 97 Buick Riviera. Started having problems with it not wanting to start

What is your question?

Thought it could be an electrical issue, a sensor, fuel injectors. After having some things replaced and taking it to 3 different shops , it still is having the same starting issue. We then noticed it only does it after weve been driving for a little bit. The other day we noticed the temperature was up to 250 when it happened again, it normaly runs at 195.