hi,i posted a while back about a noise my car was making on boost after thrashing it for a few minutes,i never had a knock link at the time and thought it was det as it was cured when i put a can of pro boost in it,anyway i've finally got a knock link and it doesn't seem to be det as its only showing a single green light when thrashing and making the noise.

so,the noise its making is like a tappety noise,i now think it could be a valve sticking if this is possible,i'm not sure if impreza valves are hydraulic or have hydraulic lifters but was wondering if this was possible??

the car is a 2001 wrx bugeye,full de-cat,tek3,panel filter,28,000 miles,full service history,silkolene pro-s 10-50,pfr7b plugs.

any advice anyone on how to diagnois this??or any different sugestions as to what it could be??

i'm sure someone else had a similar problem and think apidavid mentioned to clean the engine out,drain a quarter of the oil and replace with gear oil??,then flush and refill with normal oil and replace filter.

hopefully apidavid will read this and give me some advice.