by davejones2 » Mon Mar 11, 2013 12:27 am
Hi all.
I'm from the UK and had exactly the same issue. I've posted on the UK Legacy forum about the same issue.
I've been following this thread with interest as despite having now moved on would be keen to know if anyone ever finds a solution!
Mine was babied its entire life, serviced every 10k etc, no expense spared, UK fuel (all 95 RON+). An absolute beauty of a car apart from this intermittent problem.
I tried:
- ECU update via main dealer (from Dec 2011)
- New knock sensor
- Different fuels, 95-99RON
- Cleaning MAF
Got to the point where I was resetting the ECU (an immediate but only temporary fix) every 1-2 tanks of fuel. Caught massively retarding the timing by dealer, but no error codes.
Dealer didn't have a clue what to do next. Seemed to think the ECU update should have solved it, which it seems to do in the majority of cases if you look on most forums. Gave the car to a family member to see if they could find a fix, no luck so far.
I was wondering if it could actually be something physical tricking the knock sensor into retarding the timing. Mine had a audible vibration coming from somewhere at around 3,000rpm. Never found out what it was (sounded like a heat shield / exhaust origin if I had to guess). Did wonder if it was near enough to the knock sensor to simulate engine knock vibrations. Sounds unlikely though I guess, but worth a thought.
Replacing random sensors seemed to be the next route, one that sounded like a bit of a money pit and as such I wasn't prepared to go down.
If anyone does find a solution it seems it will benefit a large number of people!