by ward-o on 10 May 2015, 18:12
since you already own it , here's some things you can try before tossing in the towel. for starters 15w-40 doesn't cut it in the cat motors anymore. you need to run a LE or low emission 10w-30 or 40. its additives help keep the injectors cleaner, also change it on time, it gets really thick at about 300 hrs . we ended up having to do all 6 injectors . in the cat tier 3 to make the air cleaner they made the oil dirtier so soot goes in the engine oil . the same oil which is used to snap the injectors open,that's also why they start harder, gotta build enough pressure to pop em open. soot is as hard as a ruby on the hardness scale n wears out the components along with age of the return springs and number of hot /cold cycles. most honest cat guys will tell ya buy new injectors every +/- 4500 hrs. do as a set,i know it's expensive, write down all s/n on top of new ones and in which cylinder they went and then have cat "flash" them into the ecm.(takes their software and laptop, not worth it to buy) before any of that check your ecm harness plug pins , i know it's a b--ch to get to em,but if water got in, then check for corrosion and pitting on the male pins caused by water and electrolysis. use a LPS-3 type coating, not diaelectric,it causes the silicone o'rings to get soft n swell up. I bet it'll be other injector's tho.