my '88 240 GL is still at it with the oil, everything has been tended to, this is from the faq. If all of these componets have either been replaced or cleaned what else could cause oil to erupt from the filler cap?

The large hose from intake manifold to top of flame trap assembly.
The flame trap housing.
The flame arrestor, now white plastic (formerly brass).
The large lower hose from flame trap to top of "breather box".
"Breather box"
Small hose from flame trap assembly to fitting in intake manifold.
Fitting mentioned above.

Then a new problem developed. When I started it to go home from work, i had some trouble. It took some effort to start. Once i got it going, it idled nicely for 3-4 seconds, right on 1,000 rpm. then the tach just dropped and kicked back up and this continued and the car struggled to stay running. I tried reving it and started to leave, i hit the gas and nothing. Then a belt squeaked and everything kicked in and then it was off, then it was fine then it was off, once it gets warm it can manage to idle but its not pretty, very rough. i was able to manage to get it home but here it sits. i replaced the pulgs and wires when i got it, that was last year, couldnt have been more than 11,000 miles. the exaust came lose at the header, is it possible an exaust obstruction could cause this? , i ran it like that for a while, im missing the washer and just havent gone to get one. It seems simple as it was fine a few hours before and then all of the sudden this. Any ideas?