I have a 7.3 idi that has about 5000 on complete overhaul including injectors and IP , has been running fine until about 2 weeks ago and developled a mis or sputter at around 2400 and higher , i had the injectors pop checked of which 4 did not pass , replaced the 4 and still have same problem , i replace the lift pump , old one only had 3 psi , and fuel filter , i went ahead and replaced the other 4 injectors , still have problem , sitting still with the throttle at 2400 it makes a sputtering sound and when does i see a blueish colered smoke , thanks