Oil Pressure Senders / Mis-firing

[grenjs]

Background... New engine 15,000 miles ago. Engine is a 2.1L Wasserboxer Digifant. Been running fine until...

A couple of weeks ago our Vanagon GL (American import) started to mis-fire. We weren't 100% sure if it was the fuel we had just put into it, but it now appears it wasn't.

As per normal knee jerk reaction, we've been and replaced the Distributor Cap, Rotor Arm, HT Leads and Plugs (Only the plugs had been replaced in the past 2 years) and this seemed to improve the situtation 99.9% (there was only a very faint trace of mis-firing). However...

Today we went out and only did 2 miles when the van started to behave very badly. Each time we accelerated, the rev's suddenly dropped and the Oil light started to flash quite rapidly. When the Rev's got to about 1000, the engine started to pick-up again until again the rev's dropped and the oil light starting flashing.

The oil level is fine and although we can't be 100% certain, with only 15k miles on the clock with this engine, assumption is the oil pump is good.

Looking at several sites over the net, they seem to indicate the Oil Sender could potentially be the cause as they are dropping the rev's to protect the engine.

Can anyone confirm the senders would make the van behave in this way? Any other suggestions?

Thanks in advance...