PO170 code

I would start by using a scan tool to actually verify that the fuel trim is out of specification. This code can be from rich or lean fuel trim going outside the limits. However it can be a false code. With live data you can see if the trim is excessive either way. A large vacuum leak or a stuck open injector can both cause it, as can a bad O2 sensor that is telling the PCM to adjust the mix excessively. Check the intake ducting for cracks near the throttle body. If it is a stuck injector it should be running a bit poor.