Looking for help or device of reliable source to chase down what appears to be electrical problems.

I am in southern NH.

On Saturday at Limerock the car seemed to run ok for seven laps and then died on the front straight. Pulled off at the flag station after turn two. Once the car sat for a few mimutes it started and I drove back to the paddock. Checked the wiring harness at computer and thought I founf the problem with a loose connector.

Went out for the afternoon race and the car ran fine for the pace lap, but when the green came out it shut down before I got to turn one. I coasted and got off after turn two. This time the car would not start and once towed back to the paddock had to push the car onto the trailer.

Unloaded tonight and the car started fine and sounds normal.

Any recommendations?