hi im looking for a bit of info i have a 94 wrx and over the last week or so theres a low tapping noise out of the engine. it doesnt seem the same as big ends. do the bearings on the cams go in them or do valves stick undr har acceleration it seems like its only running on three cylinders i didnt get a chance to check the plugs yet thy were changed 20000km ago should they be alright

 

IF YOUR SURE ITS NOT THE BIGENDS TRY AN ENGINE FLUSH AND NEW {CORRECT GRADE} OIL/FILTER
The EJ20 in your year has Hydraulic tappets that need to pump up with oil could be a slight block.....however it sounds a wee bit more serious than that, but its worth a try...

 

how do you do an engine flush and i use 10w 60 castrol is that good or should i use something else

 

Engine flush.......think long and hard before you do that. Flush the engine through and you could be asking for trouble. Heard stories before and we are not just talking Subaru here when a flush has been done only for bearings or worse still engines let go.
No if i where to flush an engine through i'd carry out a number of oil and filter changes in quick succession. You dont want to be removing all that goodness that has built up over a peroid of time by flushing. With regular oil changes theres certainly no need for that sort of behaviour.

Running on 3 cylinders........chk

Plug gaps 0.7mm (028)
coil packs for evidance of cracks etc.

Seeing as you haven't changed the plugs for 20000km or more think i'd be tempted with a fresh set of plugs and be done with it. Still chk the gaps.

 

i have a set of ngkpfr7b to go in i'll let ya know how i get on later thanks