hi everyone im new to the forum as i just bought my first subaru yesterday

its an 1994 wrx sti. mods are a full exhaust system+decat and panel filter that i know of.

as said im havin a problem with it misfirin for about a second or so when the foot is to the floor then it will clear then go fine. i can give the car say half throttle boost will come in and car will pull fine with no problem its just when its under serious load that i have this problem. can anyone help me plz as im sure you will know.......i know nothin about these cars since this is my first one. any feedback will be much appreciated

 

Hi mate & welcome it sounds like the coilpacks are your problem take them off & pull the rubbers bacK to inspect & there more than likely be cracked there about 60 quid each though & you'll need 4, i'd also clean all boost hoses through with carb cleaner aswell

 

^as above really,but if you take the coil packs out,it would be sensible to replace the plugs while you are at it as old worn plugs can cause misfiring too, plugs should be ngk pfr6b's or pfr7b's set to 0.6-0.7mm. thanks bryan

 

thanks guys i'll check them out. is the misfiring damagin the engine at all runnin it like this? where is the best place to buy the coilpacks from if they are the problem?
"plugs should be ngk pfr6b's or pfr7b's" what the difference in the types of plugs mentioned? thanks again for your input.

 

Sure it's a misfire and not fuel cut due to overboost?

PFR7-B is a colder(think that's right) plug than the 6-B. 6-B's are recommended for standard cars with the cat in still.

 

here's a guide on cleaning the boost solenoid aswell https://www.scoobynet.com/general-te...-what-maf.html as for coilpacks id try David at API Engines on here otherwise importcarparts.com there excellent had loads from them

 

yea sounds like coilpacks defo worth changing spark plugs aswell,also could be the mentioned boost solenoid i had same on my old scoob

 

"Sure it's a misfire and not fuel cut due to overboost?"

what is standard boost for my car?

is their uprated coilpacks? if so are they worth gettin? thanks lee

 

I would check boost level first, std its about 0.85 bar i think.

 

Mines is runnin 1.1bar!

 

LOL sounds more like boost cut then.........

Even with a chip anything over 1.1bar will boost cut, its probs caused by the cooler weather we have been having.....

Mine sometimes does it too, mostly on cold damp nights.

I would check the ecu to see if its been chipped, if not lower the boost to std levels.

If it has a chip just lower it a little bit so you dont hit cut at these lower temps, its maybe prudent to do a RR run to check the fueling is ok too.

cheers

 

Well folks I don't think the misfirin will make nuch difference now as I manage to smash the car yesterday.
The car is now for sale if anyone is interest? Its the rear end that has took the impact and have pics if anyone is interested. Cheers lee