so, i received my '92 240 yesterday evening, drove it home and then to work this morning and all went smoothly save for some steering wheel vibration at around 50-55 mph and some dirt and grime from the trip down on the truck. did a little bb research this morning, and i'm thinking i should look into wheel balancing and/or tie rod ends to solve the vibration issue. then i ran through a carwash on my lunch break to solve the dirtiness issue, only to end up with an erratic idle immediately upon pulling out of the wash.

rpms at idle would rev from 800-900 up to around 1200-1300 and back down in fairly rapid succession at stops and acceleration was even more sluggish than normal. then, suddenly, while driving down the road back to my office some nice torque kicked in rather suddenly and i got some acceleration back and idle was much smoother at the next stoplight. i've done a little bit more bb research this afternoon and found plenty of erratic idle info, but was wondering if the fact that it showed up immediately after a wash and then seemed to go away might provide a shortcut toward diagnosis...any thoughts?