My sis's 2004 V-70, light pressure turbo, started running weird a couple of weeks ago--surging, weak, etc., until finally the CE light came on. Took it to local auto parts store who read the OBD-II description: "System too rich, off idle, bank 1". He unfortunately didn't write down codes. Sis went back later for codes, computer had cleared codes, no CE light on, nothing. Car ran fine. Then yesterday big time staggers coming up hill to her house, black smoke, finally dies. Waits ten minutes, restarts it with difficulty and staggers home. No CE light came on, no info on the LED display. Today she went out to garage, car started right up, no problems whatsoever, still no codes or CE light.

Car has 68K on it. Kind of low for an O2 sensor to fail in my book. Should I tell her to have a mechanic check for a leaky vacuum line or MAF meter? Any of the last two and you would think the symptoms would be permanent, not intermittent. Opinions, please! Dick