Bit jerky when cold

[Lew_VRS]

When the engine is warming up on light throttle between about 1500-3000 typically in first and second gear the car has a tendency to 'buck' or hold back for a second like a real harsh spike in the fuelling (car is standard).

It is absolutely fine when warmed up and also if I put my foot down, but don't want to give it some when the engine is being warmed up as that can end in tears. Just wondered if anyone had any suggestions? I know these 1.8T engines are common to kill coils but that's more likely to be missing when the engine is warm, not cold!

Many thanks

Lew

Edited 22 September, 2010 by Lew_VRS

[mikeyVroom]

When the engine is warming up on light throttle between about 1500-3000 typically in first and second gear the car has a tendency to 'buck' or hold back for a second like a real harsh spike in the fuelling (car is standard).

It is absolutely fine when warmed up and also if I put my foot down, but don't want to give it some when the engine is being warmed up as that can end in tears. Just wondered if anyone had any suggestions? I know these 1.8T engines are common to kill coils but that's more likely to be missing when the engine is warm, not cold!

Many thanks

Lew

Mine was like that too. Tried the throttle body clean, alot smoother after that. Do a search on this site you will find the procedure with pics, dead easy to do, amazing the amount of black gunk that will coat the butteryfly valve.

[Lew_VRS]

Mine was like that too. Tried the throttle body clean, alot smoother after that. Do a search on this site you will find the procedure with pics, dead easy to do, amazing the amount of black gunk that will coat the butteryfly valve.

Thought it might have been this after reading a few threads, probably could do with a clean and re-set.. possibly explains why it hunts a tiny bit on idle!

[Auric Goldfinger]

"Bit Jerky when Cold"

Sounds like my Wife..

[Lew_VRS]

"Bit Jerky when Cold"

Sounds like my Wife..

haha

always one, eh :p

[Muppje]

When the engine is warming up on light throttle between about 1500-3000 typically in first and second gear the car has a tendency to 'buck' or hold back for a second like a real harsh spike in the fuelling (car is standard).

It is absolutely fine when warmed up and also if I put my foot down, but don't want to give it some when the engine is being warmed up as that can end in tears. Just wondered if anyone had any suggestions? I know these 1.8T engines are common to kill coils but that's more likely to be missing when the engine is warm, not cold!

Many thanks

Lew

I have EXACTLY the same problem, and I was advised throttle body.....I have yet to try it though lol!

[matti_vRS]

i have the same problem on mine, it was at a mates garage a few weeks ago having the gearbox replaced, i asked him to run a diagnostic on it and found that there are two small splits i the vacuum hoses, im yet to replace them but i know that vacuum hoses can cause problems like this

[VRS Mike]

TB clean

[tuplavee]

Mine does the same, but I'd say it has something to do with secondary air pump, or someother "device". It stops jerking quite suddenly, maybe after 1 or 2min.

I took a peek in TB and it looked clean...

[chicken_eyebrow]

If you're starting it from cold you should let the secondary air pump do its thing for about 90 seconds. As part of the cold start procedure the pump will pump air into your exhaust manifold, but the engine is also running with the valves opening for longer so driving it straight away will make it feel jerky.

[Lew_VRS]

If you're starting it from cold you should let the secondary air pump do its thing for about 90 seconds. As part of the cold start procedure the pump will pump air into your exhaust manifold, but the engine is also running with the valves opening for longer so driving it straight away will make it feel jerky.

Hi mate I always reverse it straight out of my entry from cold and then after I leave it ticking over for 2 or so minutes (until i get really bored) but I see what you are saying, im not greatly worried about it but still can catch you out a bit when you go to pull off and through the revs it thinks, hmm actually id rather go a bit slower lol

[vrs200bhp]

yep chicken eyebrow has it there - was just about to suggest the same thing. the best bet would be to start the car up and the revs should rise to around 12-1400 rpm this is a good indicator to go on and lets you know that the secondary air pump is active. after around 90 seconds the revs should die down to 800-1000 rpm again and you should be ready to go.

i have been caught out before with the drive straight from cold and to be honest i think thats what knackered my old Secondary air pump. not a cheap fix at £200 either

Edited 23 September, 2010 by vrs200bhp

[Lew_VRS]

this might not have anything to do with it. but on a cold start and when the Secondary air pump is going if you drive while this is active then you do tend to get a very jerky, no/lack of power drive. only after this 90 second air pump routine has been completed from a cold start up should the car be driven.

Thanks mate, didn't know that at all

is it the secondary air pump that causes the engine to be a bit more noisy when stone cold dead?

Edited 23 September, 2010 by Lew_VRS

[Flybikeslee]

yup, just bin the fooker

[GarryC]

I have this problem also sometimes when cold :(

But i dont have a secondary air pump, and my throttle body is clean

Most odd but i have learn to live with it till it warms up

[Lew_VRS]

yup, just bin the fooker

What does the thing actually do? I work for a car manufacturer and know how tight they are with money a pound here or there makes a massive difference, they wouldn't want something fitted to an engine that they could do without, imagine that.. how much money would be wasted. Surely it does something else they wouldn't have fitted it in the first place?

[chicken_eyebrow]

Its for emissions and to warm up the cat quicker on a cold startup.

Even if you remove the air pump the variable valve timing is still working on cold start-up so that can make the engine run oddly until it's finished.