2000 civic ex approx. 219,000 miles. 7K miles ago I had the timing belt serviced due to mileage of vehicle. Got vehicle back and have noticed the car idles at times around 300-400 rpm's and other times its at 600-700 rpm's. The other thing that has me worried is that today was the third time when I start my car first thing in the morning and its a rough start, but when car starts it sounds like the engine is out of sequence for like the first 7 seconds or so and the car shakes and rattles until the idle normalizes and then it operates like it usually does. Also to mention since having my car back I have noticed what seems to me like a loss in power, I find myself downshifting more than I used to on the same route I travel everyday. I kinda feel like it could be a vacuum leak but I feel its related to the recent timing belt service being that the issues relates to the service done. any thoughts? ideas? all help appreciated.

 

CEL on? Timing may be off by a tooth.

 

Take your car back to the place that did the timing belt change and have them check mechanical and ignition timing (timing light/distributor adjustment).