New member needing some help

[Alexgrant23]

Hello everyone I have a 98 SOHC V6 in the UK and it is running very rough on cold start ups. I've replaced the PCV valve and the idle air control valve which did make a difference, albeit for the engine to rev quite high every time it's started hot or cold. Is there any suggestions on what I could do next to remedy this? I should point out that there are no error codes or check engine lights at all.
I'm leaning towards the EGR valve and the manifold gaskets.
Thanks in advance

 

[vroomzoomboom]

the intake gaskets overtime shrink and cause vacuum leaks when the motor is cold, and will cause it to run rough. once the motor warms up, it in most cases will start to run fine. what you can try is spraying where the intake meets the heads with brake clean and see if the motor rpms speed up. if they do, the intake gaskets need replacing.

 

[Mike65]

Welcome.

 

[chefduane]

the intake gaskets overtime shrink and cause vacuum leaks when the motor is cold, and will cause it to run rough. once the motor warms up, it in most cases will start to run fine. what you can try is spraying where the intake meets the heads with brake clean and see if the motor rpms speed up. if they do, the intake gaskets need replacing.

+1 on this^. Hard starts in the morning and rough idle until warmed up are indicators of aged/shrunk upper and lower manifold gaskets. Changing them is fairly easy and the parts are cheap. Prolly less than 38 quid at Lancashire Ford over there at Hayfield Road and A59.