Engine Cuts off when I release accelerator pedal polo (9N3)

[LVStEVE]

Hey All

I have been battling with my 2005 Polo 1.6 (9N3). It starts immediately (with accelerator pressed I always start it like this). It will idle fine with no problem but as soon as I release the accelerator it idles funny for few seconds and then switches off. I took it to a local mechanic and he did a full service ( spark plugs, oil and air filter, oil change) and I also replaced the battery but the problem still persists. Please help It has had this issue for months now and have lost the joy of owning a car.

[Ashveer03]

Accelerating while starting on a fuel injected engine is a waste imo.

Does it drive normal or is it down on power?

How did the plugs look when it was removed?

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[LVStEVE]

It hardly drives because you have to release the accelerator to change gears and than it cuts off. But what i will say is that when the accelerator is pressed even slightly it idles well

[Ashveer03]

Maybe u have a faulty throttle body.

Scan the car for fault codes and check if anything comes up. If no faults appear, clean the throttle body and do a throttle body adaptation. That should give u a way forward.

Sometimes if there are fault codes present, the ECU does not allow an adaptation.

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[LVStEVE]

Honestly I dont have an obd reader but i can clean the throttle body. Do you have a youtube video link about going about doing a throttle body adaptation.

[Ashveer03]

No, unfortunately u need a scan tool to do the adaptation. Vcds is the most common tool used.

If u don't have access to a scan tool maybe just remove the throttle body, clean it up and fit back. If the seals are damaged it needs to be replaced - no silicone must be used.

Before trying to start the engine, turn the key on, wait for about 10seconds then turn it off, you should hear movement from the throttle body as soon as u turn the key on. Do not touch the accelerator pedal.

Then turn the key on again, wait for all its noises to stop then start the engine without pressing the accelerator pedal.

If it starts and idles on its own, that's good but u still need to get the adaptation done. If it doesn't start and idle, then u going to have to scan the car for faults and do the adaptation.

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[LVStEVE]

ok thanks alot man I am going to try this for sure someone told maybe the fuel pump relay may be gone do you agree ?

[Ashveer03]

I don't think it's quite possible for a relay to give that issue. A relay either works or not. They do sometimes work intermittently aswell.

Fuel pressure on the other hand can cause idling/performance issues. You should check if u have the correct fuel filter installed.

A common mistake on this car is using a high pressure fuel filter. Parts shops supply the incorrect filter (4bar if I remember correctly) which is meant for a caddy or Mk5.

Polos require 3bar filters.

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