My 91 Firebird 5.0L TBI has started hesitating badly when cold.
In neutral idle, it alternately revs then slows in about a 5-second
interval until it stalls completely. It will rev up okay if I open it up.
In drive, with light accel. pressure, it seems to miss about every
other fire. With heavy pressure, it barely fires at all. I can get the
car to accellerate if I pump the pedal rapidly but lightly. As the
motor heats up, it suddenly starts running nearly normally. I've
replaced the fuel filter and the injectors appear to put out a
healthy spray. Occasionally the "service engine soon" light comes
on and I read an O2 sensor error code (44). Could a bad O2
sensor cause this engine operation?