* Incorrect timing: The timing belt is responsible for synchronizing the movement of the pistons and valves in your engine. If the timing belt is installed incorrectly, it can cause the engine to idle rough or stall.
* Damaged timing belt: If the timing belt is damaged during installation, it can also cause the engine to idle rough.
* Tensioner problem: If the timing belt tensioner is not properly adjusted, it can cause the timing belt to skip or slip, which can also lead to rough idling.
* Vacuum leak: A vacuum leak can also cause the engine to idle rough. When you disconnect the timing belt, you may have accidentally dislodged a vacuum hose, which can create a vacuum leak.
* Mass air flow (MAF) sensor: If your vehicle is equipped with a MAF sensor, a dirty or faulty MAF sensor can cause rough idling and other driveability issues. Cleaning the MAF sensor may resolve the problem.
* Throttle body: A dirty throttle body can also cause the engine to idle rough. Cleaning the throttle body may resolve the problem.
* Idle air control valve: A dirty or faulty idle air control valve (IACV) can also cause the engine to idle rough. Cleaning the IACV may resolve the problem.
* Faulty ignition components: Faulty spark plugs, spark plug wires, or ignition coil/coils can also cause the engine to idle rough. Inspect the ignition components and replace any that are damaged or worn.
To identify the cause of your idling problem, it's recommended that you have the engine inspected by a qualified mechanic. The mechanic can diagnose the problem and perform the necessary repairs.
