have a 98 TA with about 80k on the clock. engine was rebuilt at 30k. it always used a little oil (a quart per change) but seems to steadily be going through more (quart per 500 miles or so now). the car doesn't leak or "smoke" but does blow out a puff of dry black soot when you get on it. also find evidence of this stuff on the rear bumper between washings (once a week). also after warming up and driving for a while the oil pressure drops as low as 30psi while cruising and rises back to just over 40psi with more rpm. im gonna do a compression and leakdown check, but was wondering if this could be something other than piston ring or valve related. no coolant in the oil, or oil in coolant. the car is a stock a4 and dyno'd 293rwhp 311rwtq if that helps any. the dyno shop said my a/f was rich at about 10.5. any insight from the brain trust would be great. i'm to the point of tearing the block apart, but don't really have the time/facilities/extra vehicle to go on a wild goose chase. if its screwed i need to get a new engine.

 

bump...

 

is there oil in the intake the pcv valve could be bad or hooked up wrong and sucking the oil in.