What do you think this could be....
 

Ok, Hi Gents and Ladies, What do you ECU guru's think about this one.
I've got a 2001 WRX completley standard apart from a Cotton Green panel filter and a prodrive backbox. When i drive the car hard in 3rd, 4th when i hit about 13.9 PSI boost, the engine CEL light flashes. It doesn't stay on, just flash for a little bit. Not sure if its related but boost doesn't feel like a smooth curve, it seems to judder abit. It used to have a cheap atmospheric BOV, but i soon took that out and went to standard recirc. What do you think?

A flashing CEL usually indicates a misfire. Have you had the codes read to see what it is throwing up. Could be plugs, coil packs but without codes it would be difficult to diagnose:wonder:

Cheers Pal, Funny you should say that. I've got a reader with 'torque' app on phone, it doesn't show any historic codes......

Factory map is set for about 0.9 to 1 bar so it's not likely to be overboost, but worth checking the condition of your plugs. Also look for any hairline cracks in the coilpacks - pull the rubber sleeve off and have a good look. Could be the boost is blowing out a 'weak' spark causing a misfire:wonder:

What you think then, new plugs, think they could do with doing anyway. Is it an easy job?

It's fiddly but not difficult. Drivers side you'll need to whip the airbox out and passenger side it's easier if you remove the washer bottle. Worth getting a 2" ratchet extension for your spark plug socket and be prepared to try and squeeze your hand in once the coilpack bolt/spark plugs are loosened - easier to remove by hand if you can get them in there:thumb:

Check the tech archives see if there's a 'how to'

You think the plugs will solve the problem? I had a feeling it may be a misfire, when it flashed on CEL. Doesn't feel like it is though. I may take it to a garage to have plugs done, unless someone local to me is willing to help :-) Anyone know which plugs i should get, platinum or irridium?? Confused.com

Can't guarantee the plugs will fix it but when they only cost a few quid it's worth ruling it out:thumb:

NGK PRF6B are a good bet, you can go for a grade cooler but that's not necessary on a standard car. Personally I'd avoid iridium as I've heard too many stories about tips breaking off, but it's your choice.

Ok, when i get round to it, will get them done. Hopefully that will solve the problem :-)

Changed the plugs today, didn't take too long. Only an hour and half with 3 of us, including a light holder :-) Quite a straight forward job i must say.

Car feels so much better, a lot more responsive and guess what no CEL light :-) Happy Days!

As I said, not difficult, just fiddly. Glad you're sorted. Worth checking them when you do an oil change as mine have worked loose in the past, but I am running close to 20PSI

is it a standard rom on it or has it been mapped? you may have CEL on knock

As above mate, its standard. Its not knock, because as above the CEL doesn't come on anymore since changing the plugs. Cheers for your input though.