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Flat spot when warm?? can anyone help pleeeessseee?
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Old 08 Oct 2008, 02:07 AM   #1 (permalink)
elv
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Flat spot when warm?? can anyone help pleeeessseee?

Hi all, I own a 1998 Sti and having a few probs with it,, Whats happening is when its warm its holding back for a few seconds when the turbo comes in? it judders then goes ok'ish?? its fine when its warming up and goes like s**t off a shovel but once its up to temp its plays up,, seems like the its under fuelin or something?? the turbo is fine (checked for play in the rotor etc and it doesn't use oil which is strange for a scooby) could it be the MAF meter or possibly coolant sensor?? any ideas people,, Just to mention its a fresh import and still restricted to jap reg's, nothing has been touched as yet cos i'm not 100% on which way to do the derestriction as i'm getting different feedback for different people.. A friend told me to join and ask the guys who knew.. Hope you can help or point me in the right direction.. Regards Elv
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Old 08 Oct 2008, 07:23 AM   #2 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

Hi.

It could be the fuel. I would recommend you only use high octane fuel in your STi Import. Try Shell V-Power or Tesco's 99 ron.
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Old 08 Oct 2008, 07:38 AM   #3 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

Hi Pete, I only use high octane fuel buddy (esso supreme) it seems to be lack of fuel when I floor it, but if I build the revs slowly it'll drive thru it with no probs and it boost ok?? its strange lol been reading thru some of the probs on here and 1 guy says he had the same sorta problem and it turned out to be a faulty spark plug, i'm gonna change em today just to rule it out... will report back later.. P.s This is the best scooby site i've stumbled across on the net and i've been lokin for a few days
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Old 08 Oct 2008, 07:46 AM   #4 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

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Originally Posted by elv View Post
P.s This is the best scooby site i've stumbled across on the net and i've been lokin for a few days
Thank you very much.
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Old 08 Oct 2008, 07:53 AM   #5 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

Quote:
Originally Posted by elv View Post
Hi Pete, I only use high octane fuel buddy (esso supreme) it seems to be lack of fuel when I floor it, but if I build the revs slowly it'll drive thru it with no probs and it boost ok?? its strange lol been reading thru some of the probs on here and 1 guy says he had the same sorta problem and it turned out to be a faulty spark plug, i'm gonna change em today just to rule it out... will report back later.. P.s This is the best scooby site i've stumbled across on the net and i've been lokin for a few days

Could be MAF sensor to, start the the car when up to normal operating temp plug out MAF sensor if car dies the sensor fine if it dont then it a faulty sensor this will show up an engine check light when you unplug this but when you plug it back in it will go off so dont worry try that maybe......................
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Old 08 Oct 2008, 08:07 AM   #6 (permalink)
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Also clean the boost solenoid it could make a difference.


Link: Boost Solenoid Cleaning



All the best.
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Old 08 Oct 2008, 08:48 AM   #7 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

this kinda sounds like the same sort of problems im having as well with mine lol im kinda at the point of changing the spark plugs on the weekend now.its confusing and annoying at the same time.it takes away the enjoyment of the car worrying about whats wrong with it
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Old 11 Oct 2008, 01:55 PM   #8 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

Hi guys, I'm new to the site, (just joined trying to hunt for similar problems).

I had my car serviced which included new Denso Spark Plugs just before a trip to France
It was stuttering before around the 4,500 rev mark under acceration and I thought the service would've sorted it but it didn't

I'm going to try the link above for the boost solenoid, thanks 2002pete for the link to that btw.

I also read the thread about the engine warning light which comes and goes intermittently for me and would like to check the MAF sensor
I have a MY99 Type RA - Where would I find the MAF sensor and what should I be looking for if it is on it's way out?

Thanks in advance
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Old 11 Oct 2008, 04:31 PM   #9 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

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what should I be looking for if it is on it's way out?

Hi.


Have a look at reply 10 Link: #10 Boosting

Quote:

Where would I find the MAF sensor
Link 1: http://www.subaru-impreza.org/forum/...-diagrams.html

Link2: http://www.subaru-impreza.org/forum/...-location.html


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Old 11 Oct 2008, 04:37 PM   #10 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

Once again, thank you so much for pointing me in the right direction pete, it's greatly appreciated

I'll check all of these items tomorrow and see what I can see
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Old 11 Oct 2008, 04:49 PM   #11 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

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Once again, thank you so much for pointing me in the right direction pete, it's greatly appreciated

I'll check all of these items tomorrow and see what I can see

Glad I could point you in the right direction. Have a good evening & good luck for tomorrow.
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Old 14 Oct 2008, 03:29 PM   #12 (permalink)
elv
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Re: Flat spot when warm?? can anyone help pleeeessseee?

Hi All Taking Pete's advice I cleaned the boost valve with carb cleaner a couple of times, It seemed better but was still cutting out at around 4000rpm when hot.. I then decided to change the plugs (was gonna do it the other day but busy workin) when I removed the first plug low and behold the platinum tip had burnt out I removed the othe 3 and found 2 of them were the same.. Replaced all and sprayed the maf sensor with carb cleaner while it was off and she now goes like stink it all gears and even when hot.. Buzzin

Thanx Pete for the advice mate
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Old 14 Oct 2008, 04:02 PM   #13 (permalink)
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Re: Flat spot when warm?? can anyone help pleeeessseee?

I'm glad we could help you.
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