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Sudden power lose and jault when flooring it

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Old Nov 28, 2005 | 11:44 AM
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Default Sudden power lose and jault when flooring it

I wondered if anyone could help.

I think I have a problem with my Scooby Turbo Wagon MY99.

Was driving home one night and about 15mins into the journey I thought I would boot it and as I floored it in 4th there was a sudden jault as if I slammed on the brakes. I lifted off then accelerated again and the car was fine. It was as if someone car the power. Like I slammed it in reverse, which I know I didn't.

Thought I'd try again and at around 5000rpm the car did the same.

The car was warmed up before driving and I didn't hit the redline.

Haven't driven it since, scared.

Does anyone know what it could be?

Thank you
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Old Nov 28, 2005 | 11:48 AM
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Is your car modified?

Tony
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Old Nov 28, 2005 | 11:55 AM
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Simota panel filter, and ScoobyWorld Ninja back box and centre section de-cat and 18s, why?
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Old Nov 28, 2005 | 12:16 PM
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over boost causing fuel cut or the boost control solenoid needs a clean imho..

Simon
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Old Nov 28, 2005 | 12:37 PM
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Originally Posted by Jolly Green Monster
over boost causing fuel cut or the boost control solenoid needs a clean imho..

Simon
Ill agree on the boost control solenoid, had that problem meself, definately sounds like it.

Tony

PS, if you were running a full decat, that could also explain it as they can overboost in cold weather.
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Old Nov 28, 2005 | 01:03 PM
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I'll get it cleaned and see what happens, thanks guys
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Old Nov 28, 2005 | 05:20 PM
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I had the same scoob and exactly the same problem. I asked the guys on scoobynet a year ago and was also told that the car was overboosting. Unfortunately i wrapped up the car before i could fix it. However, i carried on using the car with no problems.
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Old Nov 28, 2005 | 07:46 PM
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Just had exactly the same problem with my bugeye WRX.

I'd nicked a hose when changing my intercooler, which meant the actuator wasn't controlling the boost.

Sorry no pics, but it was bottom left corner of the intercooler.

I think it would be best if you didn't floor it until it's sorted.
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Old Nov 30, 2005 | 11:53 AM
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Cheers guys, very light right foot for a while I think

Thanks for the advice
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Old Nov 30, 2005 | 01:01 PM
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I'm a new member here, my car started to do exactly the same thing yesterday. Very juddery, feels as though its missing when under hard accelleration.

Fairly random, no set revs or throttle position, but it doesn't do it pootling around town.

I only got the car last week, so am not up to speed with any common problems, where does one find the boost control solenoid?
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Old Nov 30, 2005 | 02:35 PM
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Graham - the above talks about fuel cut caused by overboost. It's a very violent cut, and makes you feel like your head is going through the screen.

Your description sounds more like a misfire. This can be caused by any number of things - some good, some bad. I'd strongly recommend a check by someone who knows Scoobs - worst case is the car is detting like mad due to failed/failing MAF. Or course, it may just be spark plugs too.....but if you're new to Subaru's don't take the chance!
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Old Nov 30, 2005 | 03:01 PM
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Originally Posted by dowser
Your description sounds more like a misfire.
It is quite a violent cut, the car keeps accellerating but its very juddery.

The plugs were changed about 20k miles ago (car has done 80k) and has a fairly comprehensive service history.

I thought it might be some dodgy fuel - I had to stop at a Murco garage on Monday night with the lunacy on the A40 - I tried some Optimax today, but its still doing it.

It doesn't feel like a "conventional" misfire, but as if someone has stolen the turbo and 150bhp for a split second
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Old Nov 30, 2005 | 03:29 PM
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Graham, what year of car is it? Fuel cut will stop you accelerating and you would defiantely know about it, so it does definately sound like a misfire.
The usual suspects are indeed the plugs (if they are 20k old I would change them anyway as a matter of course), if its an older classic that has individual coilpacks, then it could be them thats on their way out. They do tend to fail on the older cars.
The other suspect which you will probably hear is the MAF (quite unreliable on a 99)
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Old Nov 30, 2005 | 04:13 PM
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Looks like I was spectacularly wrong, just been outside to have a quick look only to find one of the plug leads was loose. I guess under hard acceleration it was coming away from the plug momentarily. Just driven it round the block and it pulls away smoothly, I'll try it again tomorrow - thanks for all your help.



However, jay, I read your reply with horror, it’s a 99 "Turbo Wagon" (if that’s the correct expression, it’s an estate with a turbo, anyway!) - I'll do a quick search for MAF problems and change the plugs before christmas anyway.

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