First issue with the delica.

[Chino]

Update: So, it seems now the engine is running rough, RPM's are the same but the engine sounds different and seems to vibrate more. I checked the air filter and that seems fine, checked the fuel filter again and the valve at the bottom is tight. I get power going up hills and at highway speed, just seems rough when I come to a stop in gear or pop it into reverse. Any suggestions? Is it possible that air could be in the fuel line and blocking fuel to one of the cylinders, but the other 3 carry the load?

Cheers.