What causes a rough idle and engine light after timing belt and water pump change?

My car is a 1997 Toyota Avalon that was recently tuned up. It is a car in perfect mechanical condition until recently when I had my timing belt and water pump changed. The engine light is on and the idle is rough. An Auto Zone diagnostic test determined that there is misfiring in cyclinders 1,3 and 5. Could this be related to the timing belt change, and will it cause damage to the engine? Of course the mechanic that did the work has closed shop and disappeared.What causes a rough idle and engine light after timing belt and water pump change?Yes, that sounds exactly it. Especially since it involves all the cylinders on the same side of the engine, which I'm guessing is a V-6. Sounds like they slightly miss timed the cam for that set of cylinders. As far as damage goes, if it hasn't hurt the engine yet, it probably won't. That doesn't mean you should continue to drive it. I'd look into having someone re-do the timing belt.What causes a rough idle and engine light after timing belt and water pump change?timing is off and valves are worped thats why you dont have any compretion it will idel rough if it is just a hair offWhat causes a rough idle and engine light after timing belt and water pump change?Make sure that the plug wires are on correctly and in the correct order and check the plug gap it should be 0.44 and the timing is 10degrees btc couldn't find the firing order but some one should have it make sure that all of this is correct then if you are still having this problem then go back to whoever done the work lots of luck!!!!!!!!!!What causes a rough idle and engine light after timing belt and water pump change?The timing is off a little bit. Sometimes the timing belt stretches a bit after it gets put on (a competent mechanic should know this) and the timing gear is now probably off about a tooth. It won't really hurt the engine, but the engine won't run as smoostly as it should and you won't be able to pass an emissions test with it that way.What causes a rough idle and engine light after timing belt and water pump change?it sounds like a timing issue i am not sure if the engine in that car is a interferance engine or not you could have possible bent valves if it is my advice would be to seek a qualified mechanic i hope this will help the right cam is probably off 2 teethWhat causes a rough idle and engine light after timing belt and water pump change?the timing belt was probably installed incorrectly and needs to be fixed asap. and yes it will damage your engine if left alone and you are driving a lot.What causes a rough idle and engine light after timing belt and water pump change?It's definetly a timing problem. Get if fixed quick...