Hi I got a 2008 GMC Envoy 5.3 V8 my check engine light came on and stated it had a po3400. How should I go about fixing that? Should I drive my car with this light on?
The code is a notification about the cylinder deactivation on bank one. Driving should be fine.Should I drive my car with this light on?
A flashing CEL means immediate attention, a solid CEL isn't as serious and can be addressed later.
Assuming you mean "P3400" see the following:
https://www.carparts.com/blog/p3400-code-cylinder-deactivation-system-bank-1/
https://www.way.com/blog/p3400-code-causes-symptoms-and-how-to-fix-it/
https://www.obd-codes.com/p3400
@chucktobias Thank you so much do you know if my car is a reliable car or did I make a bad choice buying it?
@charliew336 It's a 17-year-old vehicle, so its maintenance history is going to be the most important factor. Hopefully you had a good mechanic check it out before purchase. When new they were not exactly the most reliable things on the road (remember, GM was going bankrupt at that time) but not as bad as current GM offerings.