Revs bouncing on cold start, please help!

[M90SR]

Right so my car has done this for as long as I can remember and I really want it sorted now as its annoying.

If I start the car instantly when cold (so from ignition OFF to ON) the revs will bounce up and down for about 5 seconds then everything will go back to normal.
If I left the ignition in the ON position (engine OFF) when cold for about 10 seconds it won't do it. Also if the car is warm it won't do it. The car doesn't have to be normal temp as long as its been running for like 5 mins it won't do it again (although if left long enough and it goes cold again it will do it). Would this be a build up of something that occurs when the cars cold so that when I start it, it clears up?

I have changed the coil pack and the coolant temp sensor and still nothing. Not sure if it could be spark plugs as normal driving is fine.

heres a video of whats happening
http://s774.photobucket.com/user/jay_modi/media/DSC_3361_zpsnmv56mkm.mp4.html

Only recently its started doing the same thing but a bit more violently but it is really cold outside so...

 

[M90SR]

Unless it could be fuel filter? Maybe it isn't getting enough fuel through when I quickly start it. So the ECU maybe trying to compensate. Hence the waiting for 10 seconds or so works. I'll take a look at the fuel filter.
Correct me if I am wrong.

 

[Amos91]

The fuel filter should be fine, its typically the fuel regulator not holding pressure that can sometimes cause the car to fail to start on the first turn of the key. You can test this by turning the ignition to stage II twice in order to prime the fuel line.

Another thing to try is removing the crank sensor and giving it a clean up.

 

[M90SR]

The fuel filter should be fine, its typically the fuel regulator not holding pressure that can sometimes cause the car to fail to start on the first turn of the key. You can test this by turning the ignition to stage II twice in order to prime the fuel line.

Another thing to try is removing the crank sensor and giving it a clean up.

Cheers for the reply dude!
I replaced the crank sensor last year but I'm pretty sure it still done it after that, but I'll check.
Car starts on first turn it just the revs bounces 500-1500rpm. I'll try the double ignition thing also.

 

[Typhoon]

Not the automatic choke, no? Can't watch video at the minute.

 

[M90SR]

Not the automatic choke, no? Can't watch video at the minute.

Not sure how the choke can be fixed. I'll try and re video it later today because its become more violent. The car won't stall it gets pretty close to doing so though.

 

[Carbon maniac]

When was the aux belt and tensioner changed? If your tensioner hasn't been done in 36k then it might give you a tight and slack spot causing it to strain and then free up!

 

[M90SR]

When was the aux belt and tensioner changed? If your tensioner hasn't been done in 36k then it might give you a tight and slack spot causing it to strain and then free up!

Changed last year july around 3000 miles ago

 

[M90SR]

After starting it this morning I noticed that it started fine because I allowed 10 seconds for the fuel pump to prime the lines. Which has lead me to believe the fuel filter is the culprit. Gonna replace it soon and hopefully should fix this.

 

[Louis]

Mine did this but that was due to my cat blowing i believe. There were a fair few error codes that we cleared and it hasnt happened since. Mine was slightly worse really and dipped to 800 on cold starts and back up again.

 

[H182]

I have this issue too but intermittently. My exhaust was blowing at the manifold which I've sorted, it has been better since but does do it now and again. Mine drops so low it sometimes stalls, or I have to give it some gas to keep it alive till it settles down.

It has got worse since I had my injectors out to replace one, maybe it's one of the o rings? Can't be arsed looking though tbh.

Temperature doesn't matter for me though, actually seems more reliable in the frosty mornings.