Greetings,
I just purchased an very clean 99 Legacy OB (30K miles) two weeks ago and I've made a couple of troubling observations. First, when it's cold out there is a non-trival amount of valve train noise when I start it. I changed the oil to Mobil 1 5W-30 and that really helped but there is still too much noise. Second, the engine vibrates, in either N or P, between 1700 < rpm < 2700. This happens when it's either warm or cold. I put some good gas and BG supercharger fuel injector cleaner to get rid of any gunk but it hasn't helped.
The service bulletin 11-53-98 ( knock sensor thinks valve train noise is a knock) seems to apply to me. Here are a couple of questions, for those who have been down this path:
a) Will the enhanced ECU fix the problem?
b) is the dealer going to install a new ECU free of charge, or am I going to get taken to the hoop?
c) can I test the knock sensor theory by simply disconnecting the knock sensor?
Todd