Give the throttle body a clean. You just need a 5mm Allen key and some carb cleaner/WD40 or similar. I had a couple of little problems that this simple procedure cured. There's a how-to somewhere here. Takes 30 minutes ish, start to finish. I think my throttle valve was sticking around the idle position.

Tony

 

If the above doesn't work, maybe try the MAF and lambda sensor.

 

Thanks TRL, would that really be the cause of such bad cold starting?

It is quite bad at the moment, like its firing on 3 cylinders, then as soon as the secondary air pump switches off, everything is normal again, normal idle etc.

 

If the above doesn't work, maybe try the MAF and lambda sensor. Also, have a read of this:

http://uk-mkvs.net/forums/t/56052.aspx?PageIndex=1

 

It could also be the secondary air pump. The riveted body separates due to the rivets failing. Is yours quite noisy, like an old vacuum cleaner under the bonnet?

 

I have thought about a Lambda probe, I get an very sporadic mixture fault now and again, it's one of the things I have the car booked in for.

I've repaired my secondary air pump a while ago due to it coming apart, its now bolted together, have just been out to have a look and its still all in one piece!

 

i had very similar problems last week and it turned out to be the coolant temp sensor.

cost £35 from TPS. the last one i used was £15 off ebay, it only lasted 8-10 months.

 

Done coolant temp sensor, my temp gauge is still off, but getting thermostat done next week too.

 

I did my thermostat a few months ago. During the winter it was so bad that I was getting an amber engine warning on the dash. This never returned as soon as the thermostat was replaced. My thinking is that constant over-fuelling due to the cooling system running too cold was fouling the plugs a bit. Maybe you've something similar. I'd wait until the work you've planned for it has been done, then see how it is.

However, your tb is always worth cleaning, so give it a go. It's almost free to do! And your engine will just be nicer for it.

Tony

 

Thanks Tony, will give the throttle body a going over and hopefully when car has had the thermostat done that could be part of the problem.

Cheers guys.

 

Bit of an old one but did you get this resolved as I have the same problem.

Temp sensor, maf and throttle body done. How will I check if its the lambda?

I had three new colis from vw a while back under the recall, one must of been changed before I bought the car and is a none genuine one.

However had the car for two years and this only just started happening!

Thanks.

 

Have a look at this thread - clicky

All fixed now!

 

Thankyou, I have had a read and will change my rocker gasket first I think.

Is it an easy job? If its a ball ache I'll send it to the garage!

 

Myself and Golfin found that it was a mixture of the rocker gasket and the charge pipe leaking.

The rocker cover gasket is quite straight forward, have a search on Google, there are some good guides to follow, just take your time though. My tips would be;

Make sure you clean everything well - get surfaces the gasket sits between clean and dry.

I used some gasket sealant on the 4 corner edges where the gasket steps up - see guides on internet.

I also torqued the gasket down - some dont bother, but I did it for piece of mind, as it doesn't have to be very tight - 10nm I think.

Hope that helps - have a good look around on the internet though or use a Haynes manual if you have one.

 

Thanks very much for your help.

I'll let you know how I get on.