I had an intermintent PO171
On my 98 gp gt 3.8 na and found the purge solenoid hose where the where the rubber j bend is(the rubber elbow that connects the plastic line to the purge solenoid) had a crack in it and would suck air when I hit bumps etc

Thanks for contributing to the forum. Good to know. Vacuum leaks are only one possible cause of the P0171 DTC. The ones we normally get are beyond typical vacuum leaks and there are other possibilities too numerous to mention.