High Idle - ADZ 1.8l Engine

[Anorak]

I wasn't exactly sure where to put this, so happy to move if it's in the wrong area.

The ADZ 1.8l SPFI engine I have in my SEAT Cordoba idles high (just under 1000rpm) and the revs hang if I just touch the throttle in neutral, or when coming up to a stop (will hang around 2000rpm for up to 4 seconds before slowly going back to the high idle).

There doesn't seem to be any vacuum leaks, and the fuel pump and filter were recently replaced. The throttle body is reasonably clean inside, also. It's also slightly lumpy at idle, which I'm not sure whether it's linked, or just a characteristic of the SPFI system.

So, any thoughts? Thanks!

[HaydEn]

There’s a gasket under the throttle body that is problematic - possible cause of your issues


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[Anorak]

Good to know. I think that gasket was replaced only a month or two before I purchased it. I'll have to check it out.