Ok before you jump off the hook and blast me for not using the search because I have exhausted it on multiple forums and I found the best info on this one so I joined.I have so many variables involved I need to be specific about the situation before anyone would be able to attempt an informed answer.Heres the deal 1985 Suburban 6.2 4x4 700r4 rebuilt aprox. 60,000 miles ago 240,000 on motor.I removed the stock stock mufflers and replaced with Thrush Turbos.I added a cowl snorkel mostly for cold air the stock assembly had long been rotted away.It gets tricky here,I ran a tank of 50/50 wmo/diesel.Felt strong and smooth but water in fuel light was coming on under so I changed my fuel filter which I planned on doing asit is common to run through several when you start running a mix I already had one in the glovebox and swapped it got right back on the road.It got slugish,harder to start,smoking now.I changed the fuel filter again and voila new truck! I noticed egr and epr vac lines are unplugged and the vacuum pump unpligged so I capped it.Started to get sluggish,smokey changed the fuel filter again,felt good but still smoking,got on highway and burned the rest of that tank out refilled with fresh diesel from a heavy trafficked station so ot should be nice and fresh.It still feels sluggish and was downshifting to keep a steady 65mph.I want to remove the egr delete and eventually turbo.For now my concern is should I be looking at replacing injectors Ive gunked up by getting lazy with my fuel processing? More likely to look at inj pump?Could it be that Thrush Turbos dont work well on that motor?It didnt smoke at all before now it smokes pretty heavy blue-ish during warm up and LOTS of black on heavy throttle but more intake and exhaust pressure shouldnt equate to more unburnt fuel.....Ive been told you cant really run your diesel too lean so Im stumped.Im sure Im leaving something out so ask if you need more.Im starting to feel like Im UN-tuning this engine