Stuttering problems

[everitt1980]

I've got a mk1 leon cupra and have got the old secondary air pump hissing noise and had it for a while(not got round to repairing it yet) but recently had a problem with the car badly stuttering when first driven from cold. At first thought it was a misfire issue but checked on vag com for expected faults and came up with nothing. Am now wondering if its a result in the the air pump fault as only happens when cold and when engine gets up to temp it runs perfect. Anybody else had this problem or can help?

 

[james walker]

doesnt the sap just blow hot air over the cat to get it upto temp quickly... a lot of people remove this altogether, so i doubt that is the fault. if you have a hissing noise, could it not be a boost leak somewhere, not neccesarily chuck a code either..

i would remove the sai rathe rthan repair it tbh mate, its not needed and it get rid of a few pounds aswell.

 

[everitt1980]

It's definately the sap thats hissing air out cause can feel it with my hand but it's the stuttering when cold thats worrying me. When warmed up runs fine but not found any fault codes. Might just take sap off alltogether then and eliminate that.

 

[james walker]

thats the best option mate, bypass that and see where it goes from there?