knock sensor issues see if im barking up the right tree

syptoms,

car feals like its missing/stubling below 3k rpm
gas milage is 18-20 at 80mph cruise,
check engine light on. showing knock sensor code.
change plugs(what fun) just to make shure they wernt the prob.
anyway didnt change a thing
when i pulled the plugs they were white(lean???)anyway must be the knock sensors and the missing stubling must be detonation? am i right? anyway going to get some knock sensors from subaruparts.com hopefully that will do it. hopefully the motor is fine........

kinda new to the svx motor so i just wanted to verify with somone that has more knowlege.

Are you using Premium gasoline? 91 Octane or higher is required for the 3.3L. Anything lower than 91 could produce your symptoms.






Dave

[Earthworm]

Perhaps run some fuel system cleaner as well as change the fuel filter if you haven't yet or don't know when it was changed last.

its got 190 k on it.
ive always used prem 91 oct, but ive only had it a week and half (3k miles) yep alot for a week, ish anyway the problem has only goten worse since i got it. didnt notice it as much since the exhost was tost but ive fixed that and checked the o2 sensors. ill try changing the filter but it looks to have been changed in the past 2 mounths or so. ive got most of the maint records but just for big stuff not the little stuff. car has always had moble 1 run in it. trany always flushed and changed every 30k, ill update as i get the parts.

thanks

[Beav]

Knock sensors will not cause misfire.

If your car is pre '96 the ECU doesn't detect misfires, that is an OBDII monitored item only.

Normal misfire detection procedures apply here, as does normal knock sensor checks.

Misfire? I assumed it was just rough due to retarded timing.





Dave

thats what i was thinking ..

Originally Posted by red95svx

Misfire? I assumed it was just rough due to retarded timing.





Dave

[Beav]

Read his first symptom line.

Retarded timing rarely causes rough running, advanced timing will. Since knock sensors usually retard timing in 4 degree increments, usually to a maximum of 12 degrees, it is difficult to fathom a knock sensor causing rough running.