Alfa 156 JTS trembling at low rev
I have a slight problem. Whenever I rev my car (let's say above 2-3krpm) and then take my foot off the accelerator pedal, the revs stop at around 1200 for 1-2 secs then the car trembles and then it goes down to normal 900-1000. What could trigger this? There is no problem when I go up in revs, only when it goes down.
I also need to mention that I do get the usual Motor control system failure from time to time in the morning when temperatures go below 0 degrees C (the lower the temp the longer it beeps). It usually beeps for 10 secs.
Also the diagnostics dude at the dealer told me that I get an error on cylinder 3 so I changed the plugs. Haven't been there since.
Any ideas? I'm thinking battery (after reading tons of posts). Gonna have it checked tomorrow. Thanks.