QuestionQUESTION: Hi, 98 corolla(170,000Km) idles rough but drives ok. Especially when coming to a stop, doesnt stall but feels like it is going to. Putting it in neutral or park doesnt make it any better. has new plugs, wires, pcv valve. Engine light was on, replaced rear O2 sensor and light is out now.Kinda feels like it is surging or cutting out at times when maintaining a constant speed. Dont know if it is related or not but this all started after I had an exhaust flange gasket replaced, the one just down from the manifold. Checked hoses for any obvious problems as someone had mentioned vacuum leak. Just looking for some possibilites to explore. The car is in exlt. condition and ran like a top till a few months ago. It is even noisier when it is warming up in the morning. Thank you so much in advance :) TiM
ANSWER: There have been some problems with the coils on these engines, there are two of them one for each pair of cylinders, remove the coils and check them for signs of arcing to ground, an engine misfire should turn the check engine light on, you may have to drive it again until the light turns on and the let me know what the code number is,just curious but what was the trouble code when the O2 sensor was replaced?
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QUESTION: Hi and thanx. It was the PO441 code and it indicated the rear O2 sensor on the machine my friend used to read it. Funny you should mention misfire tho because that came up as well, i think as a pending code though. My light hasnt come back on since the sensor was replaced 2 wks ago, but the idle hasnt impoved at all, goes close to stall at a stoplight and shakes/vibrates somewhat.
AnswerThe P0441 code is an evap recovery leak code and has nothing to do with the O2 sensor, a pending misfire code means that the computer has detected the code once and is waiting for it to happen again before turning the light on (two trip detection logic)I would recommend replacing those ignition coils.
