Pretty much as the title says

Only occurs when cruising , press the accelerator to speed up and it goes

Vibration through steering wheel has become more noticeable last few days

Car is a 69 plate 1.5 tsi 107k

Any help appreciated

Spark plugs?

Changed them recently

Then maybe the ignition coils.

Did you run a scan?

Edited 21 August, 202521 Aug by nickytheshaft

17 minutes ago, nickytheshaft said:

Then maybe the ignition coils.

Did you run a scan?

Yeah , only got a pretty basic code scanner and nothing came up

When did you change your air filter?

Last guess after that yould n'be fuel filter of fuel pump.

The pump died on a frien's car.

It started stuttering then the engine cut off

Changed coil pack, no different.

Booked in for smoke test and diagnostic next week

Might be HT leads? or a failing crank sensor. Might be worth getting it scanned with VCDS. It can ping up things that basic scanners miss or can't read.

This might sound silly, but try some Redex in your fuel tank and run it through. If you're not doing so already, try to use either Shell V-Power or Esso Premium fuel for a couple of times, and it may sort it out

Or even Tesco Momentum 99, the octane, the detergent and E5 just the same.

??

'Smoke test' ?

Where there logged Fault codes at any time when the car checked for codes?

So has the 1.5 TSI ACT had the spark plugs changed @ 40,000 & 80,000 miles?

Any history of the Cam Belt being replaced before the changed advice in 2023 & it no longer being at 5 years / 50,000 miles.

Maybe time coming up when it needs checked, or replaced.

Recently ran archoil through it , last few thousand miles have been tesco momentum so all should be clean

Spark plugs are good

Cambelt done a couple of months ago

I've got some cheap £50 fault code reader that says all is good

Smoke test is to check for any air leaks anywhere

Edited 31 August, 202531 Aug by Brian15

Are you sure its a misfire. I assume any misfire would show up if scanned with vcds. I have a weird wobble on my 1.6tdi at certain speeds and only when I accelerate. No misfire logged and changed everything suspension related. I reckon its a drive shaft problem on mine. Weird thing is it randomly doesnt happen. Does it do it in other gears at the same revs when cruising.

On mine its felt mainly through car not wheel.

Alasdair

Edited 31 August, 202531 Aug by Alasdair1

Had it scanned for codes yesterday it came up with the below , are they likely to be the same issue

Is fuel gauge sensor same thing as and just another name for pressure sensor?

So after looking up code B103E1A and it recommending disconnecting negative terminal from battery for 10 mins , which I did and now get the following on starting the car

Normal after reconnecting the battery, just go for a short drive and they should all clear.

If the modules detect a low voltage (or no voltage) they will all throw a code. Very normal. You can usually clear most of them by taking it for a drive and going lock to lock, or just clear them with a scanner.

The P0148 code could be one of a few things, would a vcds scan pinpoint more specificly what the problem is ?

Realised on way home today that the misfire/vibration occurs when engine goes into eco mode.

This make it any easier to diagnose the actual issue ?

Could it simply be the engine switching to two cylinders in COD mode?

15 minutes ago, Warrior193 said:

Could it simply be the engine switching to two cylinders in COD mode?

COD ?

There's definitely vibration thats not previously been there

2 hours ago, Brian15 said:

COD ?

Cylinder On Demand - when the ACT kicks in/out and switches the engine between a 2 cylinder one and a 4 cylinder one.

Just checked spark plugs, quite a bit of oil on spark plug 1 , other 3 are fine.

Is this consistent with engine misfire whilst in 2 cylinder mode ?

Also noticed oil around the rim of air intake pipe when reconnecting it

Edited 28 September, 202528 Sep by Brian15

Dont think there should be any oil on sparkplugs at all. Could be a valve stem seal thats worn or bad piston rings. Try a compression test

Alasdair

1 hour ago, Brian15 said:

Just checked spark plugs, quite a bit of oil on spark plug 1 , other 3 are fine.

Is this consistent with engine misfire whilst in 2 cylinder mode ?

Also noticed oil around the rim of air intake pipe when reconnecting it

That would definitely be an indication of something wrong with number 1 cylinder - if the 'oiling' on the plug is simply due to the plug not firing correctly, your engine will effectively be single cylinder in COD mode and would run very badly.

What did the old plugs look like when you 'recently' changed them? (as you wrote last month)