i got a p0175 and a p0172 approx 7 days ago, i cleared them but they came back the following day, i installed a new air filter yesterday and so far they havent come back, i am about to go on a 2500 mile cruise up to canada, if the cels come back am i in any danger of hurting the car ? the mechanic didnt really help me, he wouldnt explain anything, he did mention that when he undid the gas cap there was no hiss, so therfore no pressure in the gas tank

also, my car failed inspection today, it had previously been in 'not ready mode', i did the drive cycle yesterday so think i cleared that, would it fail inspection for the 2 error codes even though i cleared them ?

please help