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

 

Did the CEL come on?
Did they actually check the coilpacks?
MAF possibly.

 

Believe it or not, ive seen poor battery condition cause this, or terminals faulty. Make sure your connections are tight, and Borrow someones battery charger to see if that fixes it. It's a free repair if it does!!

 

Have the spark plugs been gapped correctly ?? They are really fussy 0.7mm or even 0.65mm.
If the gap is reduced 7 the hesitation gets less , this points to the coil packs.
If the plug gap is too wide or the coil packs are weak, the boost blows out the spark causing the judder/hesittation.

All the best.

Dean

 

Before spending any more cash, try an ECU reset first:-

Scoobypedia | Trusted knowledge for everything Subaru | Knowledge / ECU Reset

 

Has some of you might remember over the last few weeks the scoobs not been very well was running a bit rough,jerking cutting out,was advised it was most likely coilpacks...


So i have
Checked MAF
Changed Coilpacks (New)
Spark Plugs
Fuel filter
Checked fault codes found nothing

i thought i had cracked it,as for a few days there was nothing at all,Only now it seems to have come back,she gets to running temp,so gauge says,but is still a bit jerky at times and cut out compleatly twice yesterday,but engine had'nt been running long,but once has been running about 20 minutes and engine is quite hot,theres no stopping her,and she drives like a dream,for the rest of the day,with nothing..

Any idea's

 

Fuel pump and it's connectors may be worth having a look at

 

Oxygen sensor. They have a Pre heat which become lazy & give erronous data when cold, But once they have a little heat in there all is well....

To check, Unplug the 02 Sensor from cold, start up & go for a run, if it runs better, it points to that.
It won't harm the car as the Ecu will just use it's base map with no fuel/air crrection from the 02 sensor.

Dean

 

I'd second that. Could be loose connections, wiring or just the pump on it's way out if it's the original still. Goodluck

 

If it was the fuel pump/connectors, Why would the car getting fully up to temp make it better ? Surely it would be worse, especially if the car is being driven on boost when hot & there is more demand for fuel from the Pump so it had to work harder Etc.

Dean

 

Don't know sorry Dean. I'm not a Subaru engineer obviously. My mates car had an intermittent fuel pump problem with his, eventually went leaving him stranded on holiday. He then sorted it with a Walbro. Our cars aren't getting any younger are they Just a suggestion anyhow. Worth checking anything to have our car's running spot on wouldn't you agree.

 

No problem.

A walbro pump is always a worthwhile upgrade, Especially like you say, Age & wear Etc, + if you have decatted & upped the boost /performance Etc.

Dean