Boost i think??? But maybe not HELP!!!

[lady-turbo-wrx]

Sorry if this is a long winded thread,but have a problem

i drive a 95 Classic WRX which until last Tuesday was going great,i then was low on fuel so filled her up with V-Power,Though had been told that v-power does not suit all cars About 1/2 mile down the road,it sort of died,then picked up,and was fine again,3 miles on she juddered then cut out,as if it had run out of fuel,but had plenty.. Started her up again drove fine for the rest of my Journey,about 40 miles.. so assumed i had picked up something from the bottom of the tank...

Then it got worse,the scoob was Hesitant,would pull back and even completely cut out,nearly causing a lorry to rear end me,as just died on me,even under normal driving it was jerky/juddery.. Took her to a garage where i was told its gotta be the coilpacks as does it while cold,but it was doing it all the time hot/cold..
So decieded on a process of elimination..

So have changes plugs,Fuel filter,checked all pipe work connections etc Now she drives a real lot better,but i still have a bit of hesitasion,though has not died or cut out,but when trying to give full beans or even half beans you get to 4000 revs in 3rd and its juddering though it does'nt cut out,when i change to 4th its fine,and picks up a dream.. never had this happen before,has anybody got any idea why this is happening,also my car runs and performs a lot better on unleaded,which is puzzling a lot of people as they tell me to run her on super,v-power etc,but since running on these i have had these problems,so dont know if connected or just a coincedence..

Any thought would be greatly recieved....trace x

[Scott.T]

did you change the coil packs or just the plugs
have a look on my website http://www.polarperformance.co.uk/coilpack.html which will show you what a really knackered pack looks like.
any sign of breakdown or hairline cracks under the rubber boot are a good sign they are poor performers.
Although they can still give a weak spark even without cracks due to their age.
approx £200 per set.

Does it drive OK under 3,000rpm with less then 0bar boost i.e when still running vacum rather then boost pressure (assuming you have a boost gauge). If it does and onls mess's above 3,000rpm and when boosting ifnot coilpacks it could be the MAF. The ECU goes from closed loop fuelling using the lambda sensorto open loop fuelling using the MAF at this point.

[willis]

you could try an ecu reset just take the battery off for an hour the ecu will sort its self out