Assuming you mean catalytic converter, if the converter is seriously blocked the engine may only idle but will not have the power to move the vehicle. You should have a "check engine" light illuminated also.
you can but it wont stay running if the battery is dead
There could be many of things wrong on why a 1986 BMW 325 I will not stay running. The most common thing that happens when a car will not stay running is because the spark plugs have went bad.
Alternator bad or wiring fault to alternator.
No car has a "cadillac" converter
Most likely is a bad ignition switch or lock cylinder.
dd
your radiator clogged up.cheaper to get a new radiator. nothing to do with the radiator cap.
If the car won't start, jump it off. While it is running, remove the positive cable from the battery. If the car dies, then your alternator is bad. If it keeps running then you may have a bad battery.
Does alt. light stay on after car is shut off? If so could be voltage regulator is defective and overcharging battery when running Does light stay on after car is shut off? If so could be a bad voltage regulator--if so may be overcharging battery Check voltage readings at battery should be around 14.2 with car running -- if much higher than this voltage regulator is bad.
Clogged fuel filter, replace.
if your ac is running and if you have a bad 02 sencor most likely it will not kill your car it depends on your sensor
car door light stay on