My 99 protege LX 1.8 standard trans.(186km's)had the following work done: timing belt, waterpump, plugs, wires, alternator belt by a mechanic. Right afterward, I noticed a rough idle,a blowing noise on acceleraction and a dry sputtering when the engine is turned off (after warmed-up thoroughly). My engine light came on a month later and ascannerindicated a problem with the catalytic converter. The mechanic cleared itand six weeks later it came on again indicating "low bank 1 oxygen sensor" (on a better quality scanner). Could anything else be causing this? I am not a mechanic. How difficult is it to replace the low bank 1 oxygen sensor if I do it myself? Is my catalytic converterat risk?

Thanks for any information.

 

It is the O2 sensor. I have a 03 protege( 2.0 l) and I had the same problem( engine seems to sputter until after 900, 1000 rpm, ).The check engine light came on, and after buying a tester, I found a trouble code, don't remember the number, but corresponded to O2 sensor , bank 1( the upper one). I replaced the sensor and everything's just fine now. I do not recomend an universal replacemnt cause that was my first choice and it did not fix the problem, not to mention the hard wiring(u have to clean cut the old wiring and atach a new connctor).