My truck presently has a P0306 code, diagnosed by the chevy dealer. on 2005 Chevrolet Trailblazer

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
When the engine light 1st came on, I checked my gas cap and it went off. It came on again and I checked the air in my tires and put higher grade gas in my truck and it went out. A few days later the light came back on. I again checked my gas cap and tire pressure but, the light wouldn't go off. Yesterday, I took my truck to dealer and was told that code P0306 was given. Rather than treat the code, I was told that the additional tests were needed requiring that the intake manifold to be dismantled for further testing of the fuel injector and to perform an engine compression test for additional $400. Is this the norm?
(1) Answer
(1) Comments
yep. sounds right. the gas cap and tire pressure had no effect on your light. you have issues with an injector and have no other recourse.