What ro do if codes are p0016 qnd p0017?

Could be an expensive timing chain issue or just the sensor telling you the timing is off. Regardless, it needs to get in for proper diagnosis. Not just a code reader diag. Depending on what it is, there may be in depth removal of components to check the timing issue which means you need to go into this somewhat committed. I highly doubt it will be too extreme, however it is a 12 year old car and these types of issues are expected.