Strange Knock Type Noise

[FullySick]

Hi Everyone,

I just purchased an auto VS and was wondering if anyone could help me out with a little problem I am having.

When my car is in Drive, but, stationary, there is a strange little knock or shudder every 4-5 seconds coming from the engine.

I am not sure if it is "missing" or it is something to do with the transmission?

It doesn't happen when I shift the car into neutral or when I am driving at any other time.

Anyone have any idea what this might be?

Thanks

[Ben6]

How severe is the knock? Could be harmonic balancer is on it's way out. Check the rubber around the harmonic balancer for cracks and deterioration.

[DannyboyDS]

sounds like a miss to me, when the car is in neutral there is less load on the engine which means (from my understanding) that combustion can occur easier.

when you put it into gear the engine is then connected to everything else and load is palced on it, meaning a stronger spark is required.

I had the exact same issue with an EA I used to own, check your spark plugs/leeds and the coil packs.

Check the howto section for some great info on checking spark plug leeds too.

[hsvpunk]

as ben6 said, fair chance its the balancer. had it go on my vp when i had it.. wasnt fun at all.
Heard a knockn sound.. didnt pay much attention to it.. then it went on me.

[FullySick]

It's probably more of a shudder/big vibration than a knock actually.

[sircruisealotVS]

if its not doing it all the time then it wouldnt be the harmonic balancer, that would be constant and rythmical in time with the belts movement, if its in gear or not.
a miss sounds more like what is happening, could be time for some new plugs and leads - any idea when they where done last?

[DannyboyDS]

if its not doing it all the time then it wouldnt be the harmonic balancer, that would be constant and rythmical in time with the belts movement, if its in gear or not.
a miss sounds more like what is happening, could be time for some new plugs and leads - any idea when they where done last?

I was thinking the same thing, as the easiest way to determine a problem with the harmonic balancer is to start the car without the belt ont o eliminate the other pulleys noises and its constant.

[-=ApheX=-]

so when you say your car is stationary do you mean at a set of lights in gear or when idleing in park?
i notice with my VS that there's significant vibrations going through the car when at lights in gear, but if i put it in nuteral then the vibration disapates and it idles smoothly.
and if this is the case you may need to get the thottlebody tuned and cleaned so when in idle state the engine shouldn't shudder.
If this dosn't seem to work then yes plugs and leads, and harmonic balancer, and if your getting har bal replaced get CAS replaced also saves alot of time wasted wondering wtf happened...