I've got a DF40 (04001f-510515) that starts up fine but almost immediately develops a rough idle. Thought it was a back coil or injector. Moved coils from cylinder to cylinder to see if the misfire followed any particular coil, no luck. Disconnected the fuel injectors while running to check & see if disconnecting a particular one causes it to run rougher or doesn't change it at all... no discernible difference. Checked the plugs, all looks well there, cleaned them & put them back. Checked compression, we're @170 on each cylinder, so no issue there. I'm wondering, does anyone know if there's a valve to check fuel pressure? I haven't been able to find one. And if so/not, what should the fuel pressure be?

Also, anything else I'm missing? Anyone come across something like this

Thanks in advance for any help,

Nate