I've had my '86 CGT for a little over a year, and in that time the engines warm-up routine has gradually annoyed the hair right out of my head. I got the car with a little over 85K on it, but it had sat for about 5 years prior to my purchasing it. I did a standard tune up prior to even starting it and it fired right up and ran like a champ. Slowly it began taking longer and longer to warm up. It starts right up when cold, and runs fine until the digital temp gauge moves a few bars to the right. At that point it starts running a bit rougher, still drivable by all means, but rougher. I have recently found that if i turn the car off (once warmed up)and then restart it, it runs perfectly. I have even turned it off with the clutch in while driving then immediately turned it back on and let out the clutch to roll start it and the problem is gone.

Originally i thought it might be something mechanical but the speed in which the problem can be remedied leads me to believe it may be a sensor that resets when turning the car off? maybe? I have no idea. Any help would be appreciated!

 

Sorry no answers here but I have the same problem except a higher idle. Occurs in the same manner though. I'd be interested to see what solves it for you. Good luck. Try audiworld too.