My son has a 1998 Blazer 4.3 4x4. His wife had just filled the gas tank and it shut off about five miles later. At first it would crank but not start. Did normal test, fuel and spark which were fine. After checking fuses and wiring including disconnecting and reconnecting neutral safety switch it now starts :screwy: and runs but if taken out of park it shuts off. It will crank but not start in neutral. Sound like the neutral safety switch? Don't want to unneccessarly spend loads of money to find fix. Shop wants $100 for the tow, $100 to hook it to the computer plus parts and labor for repair. Rockauto.com sells switch for $30
Thanks in advance for any help

Finally figured it out and got it fixed.

Finally figured it out and got it fixed.

Well...

What was the problem?