* The timing belt may not have been installed correctly. This could be due to a number of factors, such as the belt being too tight or too loose, or the camshaft and crankshaft gears not being aligned properly.
* There may be another issue with the engine that is causing it to run poorly. This could be anything from a simple spark plug wire being loose to a more serious problem with the engine internals.
* The car may simply need to be reset. After a timing belt replacement, the car's computer may need to be reset in order to properly recognize the new timing belt.
It's important to take the car to a qualified mechanic to have the issue diagnosed and repaired. This will help to ensure that the car is running properly and safely.
