RexNuts Subaru Forums

Hey,

This happened about 2 months ago and was very minor, which went away never to be seen again untill this evening.

Just then, on the way home, my car started rocking backwards and forwards and revs started jerking quite bad as i was climbing a small hill towards a red traffic light. My litte brother actually turned around and said "stop being stupid", thinking i was pushing the acceletator in and out.

Got to the red light where the car sat for 30seconds, the revs stabalised, and everything seemed fine.

Then about 2mins later, going up a bigger hill in 3rd gear, around 40-50km/h, the same thing happened. It felt like i was loosing power, and the car was struggling to make it up the hill. Got to the bottom of my driveway, and the revs were sitting at about 500rpm, but didnt sound steady. Sat for 1min, and the revs smoothed out, and i was able to make it up my driveway.

At first i thought slutch slip, but doesnt that mean the revs would be getting higher with a reduction in speed? This was jerking revs slowly getting lower to a point i had to stop.

Car is 05 STI, with VF36, TBE, Walbro, silicon intake, msr tune

Please help!

Brad.

Sounds like idle speed sensor, next time it does it, unplug & see if it stops/idles properly

EDIT- miss read, fked if i know. MSR would be the best place to call!

Cars going to MSR in 2 weeks for exhaust work.. i just hope it will be safe to drive it the 45mins to his shop.

You can try & unplug IACV, do it when engine is warmed up

At what level is your fuel?
Since it happened on hills I suspect a lack of fuel...
Or maybe your brant is playing up.

Fuel just over half. I put in $50 with 2 days ago, but Iv driven it since then on the same roads with no issues so I'm at a loss here?

When was the last time you changed your fuel filter?

Never.

Happened to me. Timing was being retarded by the ecu due to a sensor which was on the way out.

The way MRT described it was that instead of it advancing by 30 for example, it was only advancing by 10-15

Of course I forgot what sensor.

Have you spoken to Michael yet?
Since he did the tune on it not long ago he should have a good idea of what could be wrong.

Similar thing happened to me the other day. Turned into a road behind the uni, which is 100, so gave it a boot, changed into 3rd early.. and the same 'back and forth' jolt happened to me..
I'm just hoping it was boost cut, tho it didnt have the 'hitting a brick wall' effect.
Gave it a sec to recover, booted it again, and all good. Been good since :/
Was up hill too.

When you taking it to MSR?

Goes on 28th. Hopefully it makes it there.

I started it up yetersay and let it idle for 6mins, and everything seemed fine. Will take it for a drive this afternoon and see if it does it again.

Just put in half a bottle of octane booster, and took it around the block after letting it warm up.

Didnt want to boost it, but let it hold 4k rpm up a hill, and then went up the other hill in the exact same way as the other night (3rd gear, 40-50km/h, so lowish revs).

Every thing 'seems' fine. If anything, it seems to have more low end grunt (been driving my dads 2.5L Lib GT-B today, and my car seemed to have a freak load more oomph under 2k rpm..

Not sure if the octane booster is to thank? I assumed that stuff was a gimmick.

Lets hope it was just a ECU spasm, and its all back to normal!

Just recapping this thread.

Changed o2 sensor. No fix. $150
Changed spark plugs. No fix. $200

Plug back in the injector plug wire that had fallen out. Problem solved. Priceless.

Thanks MSR!

Was doing my head in, and it was such a simple fix, ahah. If only life was always that simple!