I don't know, exactly how far I went. I was on the highway and thought I heard a strange growl from the engine. Then it started to lose power and I looked down at the speedo to see how fast I was going and check what gear I was in (I rarely got to 5th gear but it managed sometimes) I noticed the oil pressure gauge bottomed out so I pulled over and shut it off...
When I checked the oil the dipstick was dry, but after a few minutes there was some on the stick. I dumped the litre of oil that I always carried with me and, since it was winter and I was on the highway with nobody around. I decided to try to make it to the nearest service center to get more oil.
Mine was caused by oil blowing out the dipstick, and that's why I spent an few hours cleaning out the EGR and making a few other mods...