Lately my 91 245 has been having some issues. When it starts up cold in the morning, the idle is really lumpy, almost sounding like a crappy out of tune v8 with a massive lift cam... THAT lumpy. As it warms up this evens out, but still has a slight hiccup every little bit. I have tried swapping ECUs, 561>951 and it doesn't seem to change much. All the engine gaskets are new. I did the headgasket for the fun of it last weekend, so the intake gaskets, along with the HG is all new.

Some symptoms/odd things:

You can hear a slight hiccup from the fuel pump area. If you shake the platform.. it makes this sound even more. If you clamp the rubber hose going to the fuel pump from the tank, it makes this same sound, but the duration is much longer.

You can hear the fuel in the fuel rail. I don't think I ever notived this before. It has a sound almost like air bubbles flowing through it similar to a toilet running and the sound of water flowing through the pipes, with a little rough light gurgling thing going on.