Hello i have a code for p0200 “injector circuit malfunction” and p0022 “camshaft position control”. It is a 2003 chevy blazer ls 2wd. I’ve replaced injectors and distributor about 1 or 1/12 years ago, been running flawlessly until relatively recently. Ill be cruising around 60-65 mph and there will be a hard misfire, then it will keep running fine for a while then another hard miss. It does it very occasionally. Idles fine, accelerates fine, only when im cruising at highway speeds. Ive replaced the ecm, inspected wiring and connector pins, still does it. Any help would be appreciated.