Golf V GTI Rattling and Knocking noise at Idle


New member
2006 Golf V GTI(BWA)
I'm struggling to fix my 2006 Golf V GTI (BWA), since it has many problems that I procrastinated for too long.
The last one, however, is the one that worries me the most.

When the engine is idle, I can hear two distinct noises:
- A knocking noise coming from the bottom right of the engine (the passenger can feel the vibration under the floor), only present at idle
- A rattling noise coming from the left/back of the engine (cannot locate it accurately) that is only present when I lift the pedal after revving.

Here I recorded a video to show how they sound.

The two noises always come together, most often when the engine is cold and they usually disappear when the engine gets in temperature (but not always). About 40% of the runs the noises aren't there.
Can anyone could give me any hints on what the noises are, and if I should worry? (I'm going to fix - or make them fixed - them anyway, but I don't know the severity of the damage).

--- Additional Info ---

The car had previous problems that I was preparing to fix (never had enough time), such as
- worn out MAF cable, makes the car run lean (since a couple of years)
- Long Term Fuel Trim is at -20 even when the MAF is reading correctly
- Rarely the cars runs rich when the MAF is working (already replaced)
- When trying to fix the fuel gauge sensor, I found some engine oil (about 3/4ml) inside the low pressure fuel pump. I don't know if it's normal or indicates a failure in the engine
- The car never boosts as it should, even when MAF is working. Sometimes it works decently (but not as it should), other times works quite bad (at the point I cannot overtake trucks)
- The water pump failed last year, leaking water. (The mechanic that replaced it also changed the timing chain.)

For these reasons I'm already planning to:
- replace PCV, HPFP, Cam Follower, Diverter Valve
- Fix MAF wiring (again)
- Take it to a mechanic for an oil swap and oil and fuel filter replacement.
- do a vacuum leak test

I use this car as my everyday car, and even if it had problems it still works enough to do my errands or go on vacation. However, this new issue makes me worry a bit. Do you think the works I'm planning to do would help with this problem?

Thanks in advance!


Passed Driver's Ed
You have 2 noises there.

1) Fuel line rattle. Very common. The short injector pulses at idle causes the plastic fuel lines to vibrate on the chassis rail. Drop the under body plastic liner on the passenger side and wrap the lines in foam pipe lagging. More revs = bigger injector pulses which = less shaking of the fuel lines. It sounds crazy, but that really is the cause, and the fix.

2) Cam chain wear. Another common problem. Plenty of online info about how to replace that. There's a DIY guide on

Long term fuel trim of -20% is a big problem. Should be 1-2%. Are you running an aftermarket intake?