Harper1

Hi guys / girls,

Its been a while since i've been on, finally bought another Subaru after a year with the evo 6.

I've picked up a black 2003 STi type UK with PPP, and can't begin to explain the differences between that and the evo! Very pleased with the car, however theres something thats niggling away (isn't there always?). If I'm driving along at low revs and quickly accelerate, the car stutters very briefly then takes off - like a very small misfire. If she's high up the revs, I dont have that problem. I'm thinking either a plug or a coil pack, and am going to replace the plugs this weekend.

Can anyone shed any light on this? Any help appreciated.

Thanks in advance!

Kyle.

Harper1

also, I'm running it on V-power

sahtt57

Sounds like it's your MAF sensor more than your plugs or coil packs, unless they are just slightly loose. If your car has been modified at all, double check you do not have any boost leaks. Plugs and coil packs also typically cause symptoms in the upper RPMS under heavy loads as well as idle. You can search here sti stumble. I'd also like to note that a slight stumble is normal with these cars, especially the STI model.

Harper1

Thanks for the reply. I know the car is completely standard except for the PPP. its difficult to tell if i'm loosing any pressure on boost as there is no boost gauge, but I'm pretty sure the tubo hasn't spooled up at the low revs when the stutter happens. Can my dealer tell me if its the MAF sensor?

dnc

Hi Harper,
I have same car/year and I get the same problem intermittently. Is it like a slight kangerooing for a couple of seconds? Mine does not make any sound like a mis-fire. My idle is not strange so don't think there is a MAF problem (have had this in previous car, totally different).

Did a search on here and it seems it is quite common(ish) and known on these cars (and I think Prodrive acknowledged this). As it only rarely happens on mine it is not much bother for me.

HTH
dnc

Harper1

Thanks dnc,

Yeh it sounds similar, except mine will do it all the time unless i'm very smooth with the accelerator. Mine also idles fine, however the hesitation is worse when the car is cold.

It doesnt sound like a misfire, it just dips very briefly most of the time when I change gear and accelerate again.

Cheers