It's so difficult to guess without being able to experience the problem first hand and at least do some basic diagnostic test. Your car has On Board Diagnostics (OBD2). A diagnostic socket under the dash allows a scan tool to be attached to interrogate the on board computer in your car, a professional grade scan tool reads trouble codes, looks at live sensor data so you can look at a sensors performance and signal without having to do intensive testing at each sensor. Was the Check Engine/Service Engine Light on prior to replacing the sensors you replaced? I hate replacing any part or component without being able to prove it is defective. As with most things automotive its best to check the basics first, check for vacuum leaks, fuel pressure and delivery, check to see what the computer that controls ignition and fuel delivery actually sees and verify engine mechanical integrity.
when i got the car as i looked it over the car was never kept up so i have been replaceing and cleaning every thing i was told the head was no good but when i took it off there was nothing wrong with it dosent burn oil just runs at low rpms so when you come to a complete stop it stalls