99 7.3 skipping at startup and smokes
My son got a 99 f250 7.3 a two years ago and it sit till he got 16. It was running and quit on a family friend and he sold it to him for just a little because he liked it. Now he is ready to start working on it but it skipped bad. We pulled the valve covers checked the glow plugs all good, then we started the truck and unplugged the injectors one by one and 1,3 and 7 did not change the motor. We checked the wiring with a meter and replaced the injectors. Now the truck runs good when warm but skips when cold. It also smokes alot on startup and never fully quits but it gets light.
Not sure of next steps.