Welcome daleh59starter engages, vehicle won,t start. Have to turn key off to stop starter. Vehicle starts after second try
Several things could cause this. First off and maybe the easier to solve is to check out the battery if it is more than 3 years old. Low voltage could cause this. There is a starter solenoid that could cause this if defective. Lastly and not what you would want is the TIMP.
(You might want to reset it by disconnecting the battery then re-hooking it back up.)
Here are some LINKS that might help if you have not already read them. Good Luck and let us know what solves your issue.