jay_jay

I very rarley let me car rev past 4000rpm

but last night i was racing an st focus , i kicked his *** but ............

My car started jerking like on off on off with boost.

Car seems to drive ok , just when i boost her a bit hard , she jerks about alot.

Car specs ,classic JDM WRX , Standard ECU, injectors etc, only mods are FMIC , TD05 turbo.

95 scooby scotty

my one does that does the engine check light go on and off?

TingTongPJ

iTrader: (24)

sounds like fuel cut from overboost, would be worse with the colder weather.

scooby72

iTrader: (6)

Or possibly a failing coil pack???

jay_jay

check engine light does not come on

my94wrx

iTrader: (4)

i would go with coil pack as well

jay_jay

could it need spark plugs? shes a bit lazy in the mornings

my94wrx

iTrader: (4)

could well do you will probably find when you check your coil packs that they will be knackered, but the up side is you can swap your plugs while you have the coil packs off.

jay_jay

how can i check my coil packs are ok ?

my94wrx

iTrader: (4)

take them out pull the rubber caps off and have a look underneath if there is any cracks, even the faintest hairline it could cause the problems you have been describing.

brashy

i had same problem with last impreza change your plugs make sure you gap them right (0.65) an check your coil packs for cracks that should sort it

madscanman2

sounds like its over boosting and ecu cutting fuel off , i ve just put tod05 16 g on my bug I, pink injectors welbro hp fuel pump , and run s like **** , spent 2 grand on engine build , need s remaped , booked it 4 next week , never use it as wont every thing done 1 st , punto is more reliable lol , been use in it 4 4 month . my pall works at subaru main dealers 4 15 yrs .

jay_jay

Ok, i reconise my coil packs have one screw to hold them onto head , but the right ones for that head have 2 screws.

could this make a difference ?

my94wrx

iTrader: (4)

were the 2 bolt coil packs secured useing both bolts? as the 2 bolt coil packs were only fitted to legacy`s as standard unless someone has fitted just the legacy coil pack or the legacy head.

mr_D

iTrader: (12)

ok i dont have the coil packs version. mine is a single coil. but i get this. and this has only started lately with the cold weather. doesnt do it all the time though

jay_jay

I dont have the 2 bolt coil packs, just my normal single bolt. which ive got fitted.

dynamix

iTrader: (3)

yes that needs mapping if you are making those kinds of mods... will always run like a bag of s***e if you change injectors to bigger ones without changing map.

brashy

jay jay just take them out an check for the cracks coz it defo sound like the coil packs have gone an change the the plugs while your there it doesnt sound like fuel cut to me coz you would no for sure if it was that fuel cut happened to me once an believe me you would no its like running into a wall then your car runs like s**t for a few secs then carrys on fine so just look at the coil packs