jwillman

The continuing saga of my CIS system.

Car runs well when warm.

Cold it starts immediately but stumbles and idles at 300-500 for about 8 seconds at which point it surges to about 2000 RPM and then cycles from 2000 down to a rough idle below 1000 and in a second or two surges back to 2000.

it repeats this a couple of times and then settles down but will nor run smoothly for another couple of minutes.

Never seen this behavior before and its really starting to challenge my patience

tailpipe

sounds like a vacuum leak somewhere

jpitman2

Does sound like an air leak - try spraying kero or wd40 (something just flammable, not fuel) on all the inlet joints and listen for a change of idle. Also down the back of the throttle body where the AAV hose goes - that hose strikes me as being prone to going hard and brittle. Also check the AC extra air solenoid and its hoses.
jp 83 Euro S AT 56k

jwillman

I will take another look but have previously replaced all vacuum lines coming off throttle body, AC valve, Aux air valve and air gallery with new tubing / hoses. Also had the intake out and replaced all runner gaskets, injector seals, air gallery to runner rubber and throttle body base o-ring 2 summers ago

Just drives me crazy that it runs so poorly on start and for the first minute or so and then settles down to run/ accelerate seemingly with out issue.

What about Decel valve, EGR etc?