1991 auto 1.6 high idle RPM, lumpy turning off then backfires

August 02, 2025, 06:34:14 PM

Hi all

I recently purchased a 1.6 auto mk2 Golf.

Driving home everything was well, but after doing ~1k miles in it I've got a slight issue.

When starting up it'll rev to 4k RPM, when put into drive it sits around 1,600 RPM.
When turning the engine off it'll run for about 10 seconds lumpily, and sometimes giving a final salute with a backfire, the backfire is pretty cool.

It's got a carburetor.

Any idea what would cause this, and how to go about diagnosing it?