Q: With the air on or off my car hesitates at take off and going up any size hill and will not go over 40 in my 2002 Pontiac Bonneville

It is possible that you could have an issue with your crankshaft or camshaft position sensor. Fuel issues may also be the cause of your symptom. It is very likely that trouble codes were stored in your vehicle’s powertrain control module based on your symptoms. If this is the case, I would recommend having a check engine light is on inspection performed by a qualified professional to diagnose the problem. Consider YourMechanic as this can be done at your home or office.

Hello. This can be caused by a number of things. Most of the time it is caused by low fuel pressure, a failing air flow sensor, or a bad catalytic converter. All of these are common failures. I will usually see if there are any codes in the computer and check the sensor readings first to see if anything comes up. If nothing does then I would test the fuel pressure and the converters for any issues. It is also possible that this is an intake manifold issue which is also common on this engine. If you want to have this repaired, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the car is hesitating] https://www.yourmechanic.com/services/car-is-hesitating-and-bucking-inspection