TD42 runs rough in the morning, then fine. Any ideas?

[webfish]

1990 Safari TD42

Just the last few days my Nissan has done the following.

1. First thing in the morning it starts fine, runs fine
2. After about 3-4min it starts to lose revs and power and miss a bit. Smokey when rev'd
3. After another few minutes it runs smooth again
4. Starts and runs fine for the remainder of the day
5. Next morning - go back to step one!

Strikes me it's a fuelling issue. Any ideas?

[tweake]

what color smoke?

picking either partly clogged fuel filter or air being sucked into the line.

[webfish]

I was thinking the fuel filter as well - especially due to that exact timing each morning. Might be an easy place to start.

[catalystracing]

Do air filter also, get it breathing and drinking properly.

[webfish]

Thanks team. New fuel filter, new air filter and all is good.