Weird idle??

[drudykj03]

I have bought a 87 f-250 4x4 6.9 auto trans. and most every time after i crank it up it idles fine for about 3 to 4 sec. and then starts to miss and idles bad, iradicly. I have to rev it up a couple times to get to idle normal, then it runs fine no problems. It does it both hot and cold. Is the injector pump going bad?

 

[tonkadoctor]

Sounds more like a small air leak in the fuel system that allows the fuel to drain back and it takes a little bit to catch up.

You need to find it because over time it will get worse and eventually stall and be a big PITA to get started again.

 

[drudykj03]

okay I think i understand what you mean.
This is my first diesel
so this is all new

 

[drudykj03]

how would I go about trying to find this leak