1998 malibu No Start

I have a 1998 Malibu and when I tried to start it this morning the key would not turn. I have replaced the ignition lock cylinder but the car will only start for a second then shuts off, anybody help?

If it's starting up and cutting right off obviously your battery and starter is working fine; I can only guess it's your engine. And if your 1998 malibuu has that 3100 V6 engine it very possible. The 3100 engine is strong and great but the due to the manufactuer gasket problem not the most reliable.

Did this start when you replaced the lock cyclinder or has it been awhile since the lock replacement ?

Check your Mass Air Flow sensor for cleanliness.

put the key in the ignition, turn it on but in the run position and leave it for at least 10 minutes.

If you just replaced the ignition most likely the theft system is keeping the car from staying running. It will have the symptoms you described. Do the following. Turn the key and try to start the car. The car won't stay running but don't shut the key off, leave the key in the on position where it automatically returns to for 10 minutes. After that 10 minutes again try and start the car, it probably won't start and again let it stay in the on position for another 10 minutes. Repeat this procedure one more time for a total of three times (30 minutes) and the computer should relearn the chip in the cylinder. Remember to not shut the key off or even to put it on accessory during this time. Also make sure the battery is strong enough to leave it on for 30 minutes because if the battery dies in the meantime you'll have to start over again. Let me know if this helped. Good luck