Sparkplug question...
 

My 'Check Engine' light has been on since I picked up my SVX 4/24 and when I ran the error codes they were for the knock sensor and something electrical associated with it (error codes: P0325 - knock sensor & P0748 - electrical).

I've added STP super concentrated gas/fuel injection cleaner and reset the ECU to see if the light would come back on... It stayed off all day, but on my drive back home I decided to take 'er up to redline and somewhere around 5500 it came back on. I'm thinking that I my engine must have a slight detonation that keeps re-occuring.

Since my fuel injectors are now clean, I can only assume it is one or more of my spark plugs. As I plan on doing a series of NA mods to my car (intake, full exhaust & performance cams) in the coming months, I figured it'll be best to just have all six changed.

What spark plug do you guys recommend that I use? Should I run the stock ones from my Subaru Dealer, or would this be a good time to put something better in?

Thanks! :D

-Chike

first, I wouldn't assume the STP product cleaned your fuel injectors. I would try a bottle of Techron (black), Redline's SL-1, or maybe Lucas UCL. there really aren't that many cleaners that work as advertised.

I would think OEM plugs are good. I put in Bosch +4s a few months back and so far no problems, but with maybe 10k miles, I can't really recommend them quite yet.

last, but not least, the knock sensor failure would , I assume, result in a less than optimum ignition curve regarding spark advance. the code is telling you the sensor failed, not that you have too much knock. this would reduce fuel economy & power output as a minimum side-effect. I have not changed one myself, but do a search, there are instructions in previous threads here and it didn't seem too hard from what I read.

The EG33 has two knock sensors - correct? One for each side of the engine.

Would it still be a good idea to change the plugs just to be on the safe side as well as replacing the sensor?

Maybe I could get a used sensor off of someone parting out their SVX...

PM me your address. I have a used sensor that worked fine when I replaced it.

unless you are pretty sure the spark plugs are giving you trouble, or you have more than 100K miles, i wouldn't replace them. On most cars I wouldn't give this advice, but with the expense of the coils and relative difficulty.....YMMV

PM sent. Thanks!:D

Funny you should say 100K miles...my car has 96,000 and I just picked her up 4/24 and I have minimal maintenance records from the previous owner.

I think longassname is selling his stock NGK plugs for 50% off - I'll see if they're still for sale.

-Chike