I have 2005 Volkswagen Fox 1.4 liter petrol engine. Around a month ago I started to notice strange thing. When I switch from 1 to 2 or from 2 to 3 gear the engine starts to stutter(This happens at around 2000-3000 rpms), however if I give it more gas and raise rpms over 4000 gear switching works just fine without any problems.

Also what I have noticed is that the engine is strongly vibrating(Especially when it's warmed up) in neutral gear while standing still. And sometimes when on idle engine simply drops rmps and goes off. The vibration goes off if I press gas slightly when in neutral gear. Sometimes when starting up the engine goes off immediately because rpms drops before reaching 1000.

One more thing that is really strange and quite frustrating that on average it consumes at least 10 liters of petrol which is quite a lot for a 1.4 liter engine.

Do you guys have any idea what could be wrong? Any answer is highly appreciated

UPDATE This was spark plugs problem. I have replaced spark plugs and now it's running smoothly.

1 Answer 1


This sounds like it could possibly be a rich fuel mixture, or low RPMs. If the RPMs appear to be at a normal rate, then my guess is that a bad O2 sensor reading is causing your car to inject too much gas and not enough air. Have you tried resetting the car computer to see if defaulting to the basic level fuel/air mixture temporarily fixes the problem? If this helps, then it would indicate an inaccurate O2 sensor reading, and replacing the sensor would fix it.

You can reset the ECU (car computer) to have it relearn fuel mixtures by doing the following:

1) remove both the negative and positive terminals from the battery (disconnect the NEGATIVE terminal first)

2) Wait 15 seconds then touch the 2 removed battery leads together and hold for 10 seconds then separate. (This imitated the same capacitor discharge that is involved with the Vagcom reset)

3) replace and reattach the terminals to the battery

4) stick key in ignition and turn to ignition on (DO NOT START THE CAR) and leave in this position for 30 seconds to allow the newely reset computer to re-learn the parts of your vehicle.

Another possibility is worn-out spark plugs causing a rough idle. When was the last time you changed your spark plugs? Copper spark plugs should be replaced every ~10,000km (Longer for the OEM spark plugs)

Finally, another thing worth checking is the camshaft position sensor. Inaccurate readings of camshaft position may cause poor idling, poor mileage, and inconsistent starting. If the above two solutions did not help, this may be contributing to the cause of the problem.

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