Greetings, members. I have a similar problem with my 99' wagon. The car is running very rough, poor acceleration, difficulty on uphills - I need to downshift to lower gear (it's a 5-spd). The codes thrown out are 301-304 (misfiring on all 4 cylinders), 325 (knock sensor), 420 (inefficient catalytic converter).
I just replaced the knock sensor - no change at all ($80 down the drain).
What now I wonder. Converter is the most expensive item - will be the last thing I'd tackle.
The car has 266K miles on it and has been OK until about three - four months ago when the drivability started to go down.
Any recommendations are welcome.
Thanks,
Alex