Power loss woes

[Moxley]

2007 2500 4wd 5.9 auto trans. I have had multiple occurrences of power loss since a trip to Las Vegas on 8 Sep. First resulted in Major power loss, took about 20 seconds to accel from 0-25mph, top speed about 55mph, level ground. J & S diesel diagnosed #6 injector hi resistance & replaced it. I did not have code reading capability at the time. Truck ran good until 13 Sep when same power loss recurred, codes p0202 fuel inj 2 circuit/open & p2146 fuel inj group 1 supply voltage circuit/open came up. Took truck to Bud's Diesel, Midway City, Ca where "pin point test" was passed. Numerous shop test drives checked good. Beginning 16 Sep, truck ran fine until 2 Oct.Drove 75 miles to San Diego & lost power exiting freeway. Significant power same as above. Parked truck for 4 hours, cleared codes p2146 & p0299 turbo underboost, restarted & it sounded much better. Power was back up to 80-90% driving back home. Returned to Bud's 3 Oct & requested they change the valve cover gasket as that had cured a similar problem at 70k miles. All good until 17 Oct when p0202 & 2146 returned. cleared them & restarted with 2146,0302 cylinder 2 misfire. Started home with approximately 80-90% power, got an engine misfire dropping me to approx 50% power, same codes as before. Cleared codes, restart & all good until codes p0202 & 2146 returned. Cleared them & all good through present. I have only taken short local trip since then with no codes.

Does this sound like an impending #2 injector failure or a short in the wiring coming to it. Any ideas will be very welcome. Thanks in advance.