Check Engine Light On problems of the 2006 GMC Canyon

Check engine light came on, I used a code reader and p0300 came up. I replaced the appropriate sensors and reset it. Truck ran fine. One week later the check engine light comes on again and this time I get a p0017 code. I replaced two of the sensors and replaced oil filter with a oil change. Now the truck is hard to start and when it does start it idles rough. I have it in the garage right now and mechanic doesn,t know what is wrong with it. From what I have been reading on here these engines in the Canyon and colorado pick-ups are bad engines that wont last. I have the 4 cylinder engine with 53 thousand miles on it that I bought used with 19 thousand on it. I feel GMC should fix these motors for free even though im not the original owner and that they know that these motors are bad. Id like tho know how much more bad stuff is out there from GMC that they know about and refuse to fix, knowing that it is there fault from the start. I have paid to much money for repairs from other gm products that I have bought. This will be my last GMC product that I will ever bye and if I can convince others not to bye their junk so be it.