That P0088 code is not a code that you wanna see. Chances are your HPFP is going south. If you're under warranty, no big deal. If you're paying out of pocket it's gunna hurt! All engine oils have certain specs. You need to have CJ-4 rated oil. Changing the oil will do nothing for you in terms of fixing that code. As far as your cruise control intermittantly not working, it could be a couple things, but my guess would be a brake switch fault. it would keep your CC from working, but not set a "Check engine" light.