JDMSTI03

This is a difficult problem to explain but i'll try my best..

2003 JDM STI with the twin scroll turbo engine.

Normally, On idle, the car runs very smoothly and you can hadly tell the engine is running when sitting in it. Now last week i noticed as soon as starting it that she was running rough. The car was rocking side to side, idle was low at 500rpm and it sounded ever so slighlty off beat like a typical impreza would. Being a twin scroll car it shouldn't sound like that!!

I drove away and thought it would clear after a few mins, 10 miles later its still doing it. I dropped down to 4th gear and overtook a lorry, as soon as i got to 5500rpm i started to hear a rasping sound coming from the drivers side of the engine bay and there was a very noticable difference in power. It was very reluctant to rev...

I arrived at my mates and explained the problem over a cuppa.. we went out to the car and everything i have expalained above had dissapeared. The car was ticking over smoothly, it sounded as it should and on the test drive it pulled strong and went through the rev range with ease and speed.

At that point i phoned TSL and they suggested i replace the plugs, so two days ago i fitted a new set of NGK PFR 7B, new air filter and dumped the engine oil as i have done nearly 5k.

Today its started hunting again and i get this rasping noise over 5500rpm with extreamly slow pull and no power..

Help... whats the matter with my car.??

JDMSTI03

anyone?

Jolly Green Monster

iTrader: (4)

possibly a gasket leak arounf the turbo area? difficult to be sure how a rasping noise is etc

Simon

joz8968

iTrader: (13)

Does sound like a big leak in either heads to manifold / manifold to up-pipe / up-pipe to turbo.

Has a gasket for a section of the headers burnt away badly or header section come loose, etc? Check all exhaust gaskets/connections of header sections, up-pipe and turbo.

JDMSTI03

thanks for the replys,

would a possible leek attribute to the very noticable power loss above 5.5k ONLY? and would it effect the engines ability to rev??

I also find it very odd that it 'self heals' and is fine for a few days... i.e today for example.. eveything thing seems to be running as it should.

DIPSY

Look for any black soot round the manifold and the twin up pipe or get the car on a ramp remove sump guard and get some one to hold somthing over the exhuast best cold and you will see any white smoke coming out were its leaking

adamobie1

Hi,
Don't know if this is the same concern, but my 2003 sti type uk, was similar to you are describing, but also noisey from the front end when cold. Found that the up pipe on the headers had a split in the flange section. Replaced with a Howard and Scott stainless steel one and now running sweet again.

Brought the part from Scooby World on the internet.

Hope this helps

Adam.

P.s. I also replaced the gaskets at both ends of the pipe with new genuine subaru ones, from main dealer, they were about £25 delivered to my door.