What now?

Branden125

Branden125

Member
EDIT - Cutting out has been solved after fitting new spark plugs (WOM info attached)

1.4 Petrol Sport, Issues that are still present:

- Lumpy idle
- ABS, Traction Control and Break light occasionally comes on but car doesn't cut out
- When under 2500rpm the car is very jumpy and inconsistent at putting down power, once above about 4mps this mostly goes away


Things tried -

- Cleaning earth / adding extra earth
- Different battery
- More oil
- Different coils
- Throttle body reset
- VCDS / OBD Scan
- New spark plugs

Next on the list is Spark Plugs because I have no history for the car and no idea when they were last changed. They didn't look in bad condition. It has been to WOM Automotive and they suggested Injectors or Fuel filter? Just wondering if anyone had any other ideas?
 

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Last edited:
Branden125 said:
1.4 Petrol Sport, Issues Present:

- Lumpy idle

- Car will regularly cut out, causing the dash to light up like a Christmas tree. This can be solved by switching the ignition off and on.

- Power steering will occasionally cut out which can also be solved with a power cycle


Things tried -

- Cleaning earth / adding extra earth

- Different battery

- More oil

- Different coils

- Throttle body reset


Next on the list is Spark Plugs because I have no history for the car and no idea when they were last changed. They didn't look in bad condition. It has been to WOM Automotive and they suggested Injectors or Fuel filter? Just wondering if anyone had any other ideas?
Click to expand...
I'd add VCDS scan to your list. Being me, it'd be at number one.
Mac.
 
Hello

What is your budget for fixing the car?

WOM have suggested that the car has a fuel filter fitted.
There are a couple of styles of fuel filter do you know which your car has fitted?
I would do that one thing WOM suggested and go for a drive afterwards.
Then you could fit new spark plugs, hopefully the wells the plugs fit in are not full of oil.

It sounds like your giving the car a service, I would carry on with that...
  • Oils
  • Filters
  • Ignition
Have you cleaned the engine bay? Not with a power washer but with a toothbrush and rag?
When you stop looking and start detail cleaning you find broken and worn out components.

Good luck 🤞
 
rotifer II said:
Hello

What is your budget for fixing the car?

WOM have suggested that the car has a fuel filter fitted.
There are a couple of styles of fuel filter do you know which your car has fitted?
I would do that one thing WOM suggested and go for a drive afterwards.
Then you could fit new spark plugs, hopefully the wells the plugs fit in are not full of oil.

It sounds like your giving the car a service, I would carry on with that...
  • Oils
  • Filters
  • Ignition
Have you cleaned the engine bay? Not with a power washer but with a toothbrush and rag?
When you stop looking and start detail cleaning you find broken and worn out components.

Good luck 🤞
Click to expand...
Unfortunately the budget for repairs is whatever is left after payday 😬
 
Are you sure it’s not the ignition switch? I had similar on my tdi. It would start and sometimes stall shortly after starting and all the lights on the dash.
 
Update - After new fuel filter and sparks plugs, seems to be running smoother but still quite jumpy at lower revs.
 
Two questions.

Firstly - what is the battery / alternator like? If the voltage drops while you are starting the car this can cause the throttle body to not quite reach the ends of the startup calibration sweep that in turn can result in EPC / engine light coming on with associated throttle body error messages related to not reaching minimum position (due to the voltage), and in turn another message saying that the throttle body has not achieved calibration. Normally though the car will be driveable and the lights will go away if restarted once warmed up (this is not the same as it not completing adaptation if it has been removed or cleaned where the throttle response is like a beginner having an attack of kangaroo petrol and doesn't get any better by being driven).

Secondly - what condition is your pre-cat lambda in - and is it an original quality/spec? This for me is probably the more critical question.

With our £350 AUA car, we had exactly the same issue as you've been describing despite replacing plugs (4 different plugs found when replaced), leads (original, perished-looking), catalytic convertor & exhaust (original failed due to liberal amounts of excess fuel going into exhaust due to original dead lambda and other issues which was replaced by a no-name part along with new cat at first MOT in 2019), new EGR (original was dead), new TB (original was very dirty / full of tar), oil lid, fuel lid, coil (this solved a persistent hesitancy around 1500-1800rpm that eventually deteriorated in damp weather into running on 3 and then 2 cylinders, which wasn't great - but eventually became obvious that the coil pack was cracked and sparks were leaking to earth on the engine block), but was still hunty while warming up and low throttle openings. However, it was running, somewhat more fuel efficient than it had been previously and not as prone to engine lights or obviously shutting cylinders down due to misfire, but still seemed to take an age getting to a smooth idle warming up and could be jumpy when pulling away in 1st / 2nd, although in 2020-2021 this car wasn't getting used much as my other half was furloughed by the University for childcare. Only occasional error with all the warning lights coming on described elsewhere under specific circumstances (not relevant for this post).

Eventually got to a point through 2022 where there was a gentle smell of unburnt fuel when idling on the driveway rather like an older car running with the choke out and an error finally produced itself manifested as lambda heating circuit sporadic issue.

As the lambda fitted by garage in 2019 to resolve the original over-fuelling issue was a non-original with plug spliced on, I bit the bullet 2 years ago and obtained an NTK original (NGK/NTK LZA11-V1 Oxygen Sensor) complete with correct connector and got this fitted in January '23.

Now when I start the car, there are around 20-60 seconds of slightly hunty idle (1000-1200rpm) depending on exactly how cold it is outside, but clearly either as the lambda heater hits temperature or the coolant hits a specific temperature you hear the engine note change and the idle settles down to a perfectly consistent level without the 200rpm fluctuation at around 1100 that gradually increments decrements down 100rpm every so often as the car warms up. This didn't happen before. Moreover, you can head off the drive and pull away smoothly at low speed without any jumps or uneven acceleration - it took a bit of delicate balancing of clutch and throttle previously.

The genuine spec lambda was fitted just under 2 years ago. Car fuel economy improved between 10 and 15% immediately from that one change alone and the key thing is that the warm-up cycle is now manifestly more efficient because the idle speed feedback loop is clearly much more effectively controlled, and I suspect that this is also manifest throughout the rev range.

Edited to fix inaccurate word choice.
 
Last edited:
Branden125 said:
Update - After new fuel filter and sparks plugs, seems to be running smoother but still quite jumpy at lower revs.
Click to expand...
WOM cleared, what looked like a number of historical DTCs. You should now get the engine scanned again, where any DTCs are likely to relate to your current symptoms.
Mac.
 
Update as of 7/1/25 -
- "New throttle body"
Fitted a new throttle body that has come off an Ibiza, after driving it around the same symptoms are still present, also did another VCDS scan attached below
 

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