like the title says my 1988, 7.3 na hates life unless its in a gear, but in park or N. it hits and misses terribly, but not rythmically. i thought it was a air intrusion issue, but no dice, i have replaced all of the return lines, boots and o rings, to no avail. i replace the burnt out coolent temp. switch, replaced the dead vacuum pump, tried diesel kleen in the filter to loosen anything up. any other ideas. ITs a wierd issue because once its in gear its happy but whe its just idling unloaded it shakes rattles and smokes.

 

Have you Checked your timing? does thje truck smoke at idle?

 

timing is this weekend and it smokes a grey ish haze, and smells of unbernt fuel,

 

injectors sticking?