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Master Class Auto
Master Class Auto, ASE - Master Auto Technician
Category: Car
Satisfied Customers: 253
Experience:  20+ years, full time experience. Specialize in Diagnostics & Electrical
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Hi i have a 2004 mk triton v6 3.0lt.It idles to high [1400rpm]for

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Hi i have a 2004 mk triton v6 3.0lt.It idles to high [1400rpm]for around 15seconds then drop down to 900rpm once warmed up.It does this every time i stop.I have replaced the plugs,fuel pump,fuel filter.Had the injectors done.ecu test,fuel pressure test,fuel treatment,oil change,leads and coil packed tested.Also replaced the idle speed motor.My mechanic says there is no more they can do.Can you please help.Thanks Mark

I HAVE ALSO REMOVED THE THROTTLE BODY AND CLEANED OUT.THERE SEAMS TO BE VERY LITTLE VACUMN ON THE THREE OUTLETS ON TOP OF THE THROTTLE BODY.

HiCustomer

1) Are you in Australia?

2) Your idle is elevated, even with engine warmed up, after you make a stop?

Best,
Master Class
Customer: replied 8 years ago.

YES THE CAR IS IN AUSTRALIA.WE LIVE AROUND SEE LEVEL.IT DOES THIS WEATHER IT IS A HOT OR COLD START/RUNNING.SOMETIMES IT ALSO MISSES ON ACCELERATION.THIS HAPPENS EVERY TIME I PULL THE CAR TO A STOP.

I HAVE EVEB TRIED TO LOWER THE REVS TO AROUND 400RPM BY LEAVING THE CLUTCH IN WHEN I STOP.BUT IT PULLS THE REVS UP BACK UP TO 1300RPM WHEN THE CLUTCH IS DEPRESSED.THEN GOES BACK TO IDLE AROUND 900RPM 15 SECONDS LATER.HOPE THIS HELPS

HiCustomer

OK thanks for update.. Will be answering this as soon. I need to look further into your vehicle, as it differs from the USA exports of same year. (meaning the VW's that were sold to US customers)

Best,
Master Class

Hi Webplumb,

 

Sorry for delay. You see, I do some background checks on cars sold outside USA. (I live in US and all my books, data and computer data is more geared to US vehicles we sell or import here) You'd be surprised at the equipment and emissions differences from Country to Country!

 

At any rate, there's no system or equipment I came across that concerns me. I have some ideas that will help you quite a bit.

 

First off, your engine shows poor performance. That in itself gives me some immediate direction because of the other symptom. You have a hanging idle as it's called, for one. And - you have what appears to be a misfire as well.

 

Let's do some quick checks >>

 

Obvious things that can cause elevated idle and poor performance:

 

1) A vacuum leak at air intake. This can be anything from an intake manifold gasket cracked at an intake runner, to a vacuum line going to intake, or a leaky power brake booster. Does this problem ONLY happen when your foot is on BRAKE pedal? Try it out. When it acts up release brake. Any change? Try this too: Apply brake in neutral, wait 5 seconds or so and release.. Any change at all?

 

2) As stated above, a vacuum leak, AKA "unmetered air" can cause high idle, stalling and/or poor performance and misfires. Can cause one, some or all of these symptoms. Can cause other symptoms (not listed here) as well.

 

3) Similar to above scenario, when the large, rubber/plastic air intake TUBE mounted to the Throttle body - and then connected to MAF (mass air flow) sensor has a CRACK in it - you have vacuum leak type symptoms most often. This is unmetered air. Check this tube and clamps for it as well, at the MAF.

 

Who tested your fuel pressure as stated in your initial Question? Did they test fuel volume as well? Have you access to a scanner? You may Accept this Answer if you choose. If you do so now, I am definitely here to see this thru. So feel free to post back as needed.

 

Best,

Master Class

Master Class Auto and 11 other Car Specialists are ready to help you
Customer: replied 8 years ago.
Thanks iv,e checked for leaks around the intake area.None found.Performance and economy are good.If i drive hard it runs fine[no missing] It only misses ,runs rough when i drive steady but not all of the time?The idle has become slighty better in the last day of driving.The ute has only traveled 65.00kms since new.I feel like it is a fuel problem [starving]could it be the fuel pressure regulator playing up?.I dont know how they tested the fuel pressure.Thanks Mark

HiCustomer

 

Fuel pressure and volume should be tested. have you scan tool access?

 

 

Master Class

Customer: replied 8 years ago.

I would have to book it in somewhere to get this done.I have had a scan done last week,no codes came up

HiCustomer

 

Please let me know. I have other checks that would follow. But my detailed Answer above should really do it for you. Just foolow thru it. When you have a hard to solve issue like you do here, it is proper, and pays off, to start with basic tests and work up from there - so long as there are no trouble codes that give us a circuit to inspect first. OK?

 

Best,

Master Class

Master Class Auto and 11 other Car Specialists are ready to help you
Customer: replied 8 years ago.
HI I WILL TAKE YOUR SUGGESTIONS TO MY MECHANIC AND SEE WHAT HE CAN DO.IT MAY BE A WEEK OR SO AS THIS IS A WORK CAR AND IS ON THE ROAD ALL DAY EVERY DAY.THANKS AGAIN.

HiCustomer

 

No worry... Stay in touch over this!

 

Best,

Master Class