hi folks just wondering could you please help me out. when i cold start my car in the mornings there seems to be a rattling sound coming from underneath the bonnet for no more than 4 seconds then sometimes i get a lumpy idle up and down the rev range.any ideas? thanks!
When were the coilpacks and plugs changed ? Mine started to run lumpy from cold until the coilpacks eventually went. I changed all four and the plugs and its been fine since. The rattling noise is probably the engine struggling to make power, and is shaking everything. Check all your vac hoses ect to.
hi richard thanks for the response. the coilpacks were changed quite recently by vw.the spark plugs were changed yesterday as the car was due a service.73k aum engine. all hoses were checked,no cracks,leaks or splits. my mechanic seems to think its the hydraulic tappets. with the fluctuating needle on the rev counter going up and down i was thinking it could be either the coolant temp sensor or a stabiliser valve? thanks in advance.
would a baileys atmospheric dump valve have anything to do with this? i didnt fit it,as it was in the car when i bought it.
This may well be your problem. The 1.8T engines are designed to run using recirculation dv's, as the one's which dump to atmosphere cause running problems and can put your car into limp mode. If you can, try and change back to an original or a forge recirc dv. It may well solve your running problems! I wouldn't think it would be the tappets tbh. Have you changed the oil? And does it have history of oil changes?
the car does indeed have a history of oil changes.the car had a full service yesterday. my mechanic asked me to buy lucas oil stabiliser. so you think the starting rattling issue is not tappets then?