hi there

my STI V2 have started to run very poor, CEL is not on, the car drives fine off boost but once past 4000rpm, the car jerks??? alos fuel cuts but not often....

the car just had some new plugs, no engine mods, STI panel filter, HKS Cat back system, HKS SSQV, thats it.....

can anyone tell me whats wrong with it??

 

anyone??

 

Did you check the plug gap before fitting?

Should be 0.6/0.7mm

My new plugs came with a 1mm gap

 

yes did check before fitting

 

could be your coilpacks

 

it didnt misfire???

 

What fuel are you running?
and also when the car jerks, is this in like 5th gear?

Tony

 

only uses optimax!!! it jerks on 3rd-5th gear....

 

It is not unknown to have a cracked plug. If the plugs are the only items that you have changed sinse the problem started to occur, it must be ignition related. I personally would take the plugs out and try a different set. The worst that can happen is that you'll have a spare set of plugs!

 

will try that tomorrow!!

thanks

 

I would also fit a knocklink, you can buy them from www.jap-innovations.co.uk as you can get bad tanks of optimax, and personally id run octane booster as your car is mapped for 100 ron fuel, not 98
As above though, check your plugs, they should be a 7 rating, not a 6, this can cause det if you have the wrong ones in, that can lead to engine failure (also see knocklink as it will show you signs of this).

Tony