Just got the truck back about 2 weeks ago from injector replacement. Installed a Hyperpac on level 2. First 2 tanks of fuel good while towing my fifth wheel . Mileage 11.8 10.8 then several tanks at 8.5. What's this about. Engine running good except throwing a p1093 code, sometimes it throws the code right after I reset it. Help any Ideas.

Why were the injectors replaced? A P1093 sets when fuel pressure in the high side (pump output) in not enough. This could be caused by a high side leak, insufficient fuel volume to the pump, etc. The best thing to do is check the injection pump output, it should ramp up to 160mPA all day long, hot or cold. Also check the amount of vacuum at the fuel filter fitting, it should not exceed 6 or 7 inches at 2500 rpm. Another thing to check is the fuel API, 39 or 40 is good. Good luck, -hoop

Injectors were replaced because of white smoke poor mileage, loss of power.and we were covered under the 200,000 mile warrenty. First week good now mileage is bad and put out a p1093 code. Thanks Hoot!!

Maybe it is time to visit the dealer again....