I have an Octavia vRS that intermittantly has a lag in power. I have changed the MAF but it still occurs. Sometimes when I drive, it is perfect. Power is there in 6th gear at aboout 60 MPH. Other times, I have to drop to 5 gear and sometimes 4th just to get it to accelerate. I'm not much of a mechanic, but if anyone can point me in the right direction?

Welcome to Briskoda - I see that was your first post

Is the car remapped?

Possible Diverter valve is it a petrol?

DV's a good shout, definitely - on the TFSi.

Welcome to Briskoda - I see that was your first post

Is the car remapped?

Not remapped, and it's the 2.0TDi 170 PD. I have also noticed that when it is acting dodgy,,, the Idle RPM rised from 750 to 1000.

Thanks for your replies guy's

Ah OK. Stick a bit more info in your profile about your car

Won't be the DV then!

Are you having much DPF re-gen on the PD170? Checked condition/changed air filter?

I have done Air / Oil filter change, oil change. I was told it had just had a fuel filter change (But it was from the dodgy dealer) so I can't prove it has, although he did dhow me a print out of the things he'd ordered on this car. I have has the DPF light come on once, but that burned off ok after about 12 miles. I will update my profile.

When you request power, it is a case of it feeling sluggish as if it's not on boost, and then picking up again - or is there just no power there at all, and you're actually forced to gear down?

When you request power, it is a case of it feeling sluggish as if it's not on boost, and then picking up again - or is there just no power there at all, and you're actually forced to gear down?

It is as you say Wardy, "it is a case of it feeling sluggish" It's as if the Turbo isn't kicking in until anywhere around 2500 / 3500 rpm.

Not remapped, and it's the 2.0TDi 170 PD. I have also noticed that when it is acting dodgy,,, the Idle RPM rised from 750 to 1000.

Thanks for your replies guy's

Sounds like a dpf re-gen to me, mine does this it feels slugish around 2k rpm when the re-gen kicks in and out

mine can be a bitch if you are cruising along at 60 the rev will be just below the 2000 or so that the re-gen requires and feels strange also the fact that when the car is stopped the idle stays at 1000 is a re-gen when its finished the cycle it drops back down on mine, when it does it on mine i drive home in 4th or 5th to keep the rev above the 2000 and once the cycle is finished its back to normal

Sounds like a dpf re-gen to me, mine does this it feels slugish around 2k rpm when the re-gen kicks in and out

mine can be a bitch if you are cruising along at 60 the rev will be just below the 2000 or so that the re-gen requires and feels strange also the fact that when the car is stopped the idle stays at 1000 is a re-gen when its finished the cycle it drops back down on mine, when it does it on mine i drive home in 4th or 5th to keep the rev above the 2000 and once the cycle is finished its back to normal

Thanks for that Dallan, I will try giving it a good blast, or leave it in 5th. After all, it IS a performance car! Thank's to fuel duty, i try to drive economically.

I don't suppose you know if these cars are ok on bio diesel or is that something to stay away from?

Edited 10 August, 201114 yr by Deneo

60 in 6th will be one of those points in the rev range I feel, so I'd avoid trying particularly vigorous acceleration from this point in 6th - for the sake of the clutch and flywheel

Check the handbook on the bio-diesel issue. I think they're OK to accept upto a certain % of bio.

I would also try a bottle of Millers EcoMax in there, run that at double-strength for a few tanks and that will help clean things up, as well as improving driveability (in my experience).

60 in 6th will be one of those points in the rev range I feel, so I'd avoid trying particularly vigorous acceleration from this point in 6th - for the sake of the clutch and flywheel

Check the handbook on the bio-diesel issue. I think they're OK to accept upto a certain % of bio.

I would also try a bottle of Millers EcoMax in there, run that at double-strength for a few tanks and that will help clean things up, as well as improving driveability (in my experience).

I Have added a bottle of jlm diesel particulate filter cleaner, so will wait for that to go through. When I first purchased the car, I added in some BG 44K. Is millers any different to this?

Not used either of those, so can't be sure. Millers is basically additives plus cetane booster.

DV's a good shout, definitely - on the TFSi.

This is exactly what is happening to mine feels like a 1.6 lol come on boost and its like the kettle is ready i've got the cups and the milk out lol

OP- Sounds as if you need to double dose the millers and take it a good spanking for an hour or two i had to do the same with my 5 series diesel became a chore after a few months.

A nice later revision DV for you then Grizzle

I see you might be 'WALK'ing soon too

Seconded on the 'Italian tune-up' approach; just make sure everything's nicely upto temperature. Does make me glad I'm DPF-less....

Wardy, you're a star. I added the JML, it apparently reduces the carbon burn off temp by 150 C (http://www.dieselparticulatefiltercleaner.com/Random-artikelen/jlm-diesel-particulate-filter-cleaner-diesel-particulate-filter-cleaning.html) Drove home in 5th. car has stayed at 750 rpm and is driving like a dream. Even better, I can tell the better half "I need to drive fast as it makes the car run better" :-)

I wonder if by adding the BG 44K I caused this issue myself. When I purchased the car, it was driving fine. I bought this stuff as it said it cleans the injectors and clears carbon build up off the cylinders. Maybe it did a good job and clogged my DPF, ss it was a couple of weeks later when the DPF light came on. It did go off after I burned it off over 12 miles though. Will try the millers after my next service.

Thanks guy's for your help.

Edited 10 August, 201114 yr by Deneo

A nice later revision DV for you then Grizzle

I see you might be 'WALK'ing soon too

Yeh going to nip to TPS and get a price for the Revised D version, and yeh WALK'ing is next on my list big time, cars in the garage on thursday for a new clutch release bearing, starter motor, replacement aircon flap, n80 purge valve the wonders of warranty.

Wardy, you're a star. I added the JML, it apparently reduces the carbon burn off temp by 150 C (http://www.dieselpar...r-cleaning.html) Drove home in 5th. car has stayed at 750 rpm and is driving like a dream. Even better, I can tell the better half "I need to drive fast as it makes the car run better" :-)

I wonder if by adding the BG 44K I caused this issue myself. When I purchased the car, it was driving fine. I bought this stuff as it said it cleans the injectors and clears carbon build up off the cylinders. Maybe it did a good job and clogged my DPF, ss it was a couple of weeks later when the DPF light came on. It did go off after I burned it off over 12 miles though. Will try the millers after my next service.

Thanks guys for your help.

Glad you're sorted

Yeh going to nip to TPS and get a price for the Revised D version, and yeh WALK'ing is next on my list big time, cars in the garage on thursday for a new clutch release bearing, starter motor, replacement aircon flap, n80 purge valve the wonders of warranty.

Spotted that kit on Mk5 forum, but not got enough spare for it this month...

Glad you're getting all those bits sorted under warranty mate! You do seem to have been quite unlucky with that one - still, least on the positive side all the bits should be sorted by the time they're finished

On the Bio diesel issue - DON'T

VAG don't have any of the recent engines listed for running on bio - in fact they recommend against it.

You can order for certain countries a Bio version that has different seals all the way through the fuel system. The seals in the standard models will deteriorate very quickly if you run bio - you will be looking at injectors, fuel pump, all sorts to replace!!

Check your handbook - I am pretty sure it is covered and it states that you cannot run on bio.

On the Bio diesel issue - DON'T

VAG don't have any of the recent engines listed for running on bio - in fact they recommend against it.

You can order for certain countries a Bio version that has different seals all the way through the fuel system. The seals in the standard models will deteriorate very quickly if you run bio - you will be looking at injectors, fuel pump, all sorts to replace!!

Check your handbook - I am pretty sure it is covered and it states that you cannot run on bio.

Cheers Andyvee. I will stick to regular diesel :-)

There will no doubt be someone along in a minute who says it is fine.

Have a read of the VAG Biodiesel statement here.

Not approved for PD or CR engines basically, or with a DPF.

Important:

• Vehicles that do not have the factory preparation for Biodiesel cannot use 100% Biodiesel.

• Vehicles fitted with a Common Rail fuel injection system cannot use 100% Biodiesel.

• Vehicles fitted with Pumpe-Duse injectors cannot use 100% Biodiesel.

• Vehicles fitted with a Diesel Particulate Filter (DPF) cannot use 100% Biodiesel, however EN590 containing up

to 7% Biodiesel is approved for use with DPF.

• 100% Biodiesel vehicles cannot be used in temperatures below -10°C.

• The use of 100% Biodiesel may slightly reduce the driving performance of the vehicle and slightly increase the

fuel consumption.

• The use of 100% Biodiesel may increase the frequency of the maintenance schedule on the vehicle.

There will no doubt be someone along in a minute who says it is fine.

Have a read of the VAG Biodiesel statement here.

Not approved for PD or CR engines basically, or with a DPF.

Important:

• Vehicles that do not have the factory preparation for Biodiesel cannot use 100% Biodiesel.

• Vehicles fitted with a Common Rail fuel injection system cannot use 100% Biodiesel.

• Vehicles fitted with Pumpe-Duse injectors cannot use 100% Biodiesel.

• Vehicles fitted with a Diesel Particulate Filter (DPF) cannot use 100% Biodiesel, however EN590 containing up

to 7% Biodiesel is approved for use with DPF.

• 100% Biodiesel vehicles cannot be used in temperatures below -10°C.

• The use of 100% Biodiesel may slightly reduce the driving performance of the vehicle and slightly increase the

fuel consumption.

• The use of 100% Biodiesel may increase the frequency of the maintenance schedule on the vehicle.

much appreciated my friend I'll steer clear. It's only about 12p cheaper anyway

Edited 10 August, 201114 yr by Deneo

much appreciated my friend I'll steer clear. It's only about 12p cheaper anyway

A couple of years ago my son decided to run his Peugeot 1.9D on biodiesel and for a few months it was fine, he saved money and the exhaust smelled of bhajis etc until suddenly it started p*ssing diesel everywhere and it cost him several hundred quid getting his fuel system seals replaced. Lesson learned. Steer well clear.

Bob.

A couple of years ago my son decided to run his Peugeot 1.9D on biodiesel and for a few months it was fine, he saved money and the exhaust smelled of bhajis etc until suddenly it started p*ssing diesel everywhere and it cost him several hundred quid getting his fuel system seals replaced. Lesson learned. Steer well clear.

Bob.

Cheers Bob, will do