problem started a while back after I had swapped my factory nozzles out for some used ddp50's and has run like crap with poor fuel economy and worsened performance, ok so finally got around to pulling injectors out and sending to my local bosch common-rail authorized injection shop, and tested, they failed on return flow bad and had a large spread on flow between them, so 6 rebuilt injectors and one new nozzle later they are all within bosch specs (other than 50hp flow increase), I reinstall them being careful of procedure to avoid leaks with cross over tubes (tighten injector hold downs then backing off then installing cross over tubes to just barely snug, tighten back hold downs and torque cross over nuts to 40 ftlbs) so after driving the truck is still acting up and under wide open acceleration in high rpm's the truck bucks in and out and some times truck feels weak and other points pulls like a freight train, I found a Chrysler checksum procedure to follow but curious if this sounds familiar to anyone and something I could skip right to. haven't watched or check rail pressure. but problem never had a problem until I swapped nozzles and now I know injectors and nozzles are good and fresh off of test bench. also it keep throwing a code for fan speed? doubt its related but not sure?