Yesterday my Clio 197 developed a misfire during normal driving without any obvious reason and it is happening across the whole rev range. It sounds like bad air/fuel mixture or like that timing is out. There is also smell of unburned fuel from the exhaust. I suspect that I have bad downstream O2 sensor after looking at obd2 logs. It doesn't show any meaningful readings and I have removed it from the car and tested it with volt meter and torch with the same results. I was wondering if the bad downstream O2 sensor could be the the reason why the car is running so rough and what other things should i check. Thank you wery much for your help.
I have tried different spark plugs with the same result. Did a compression test and it is the same on all cylinders. I have a LPG system installed and it is running rough on both fuels so I think that injectors are fine. It's not like it's running on 3 cylinders, more like all of the cylinders are misfiring. Maybe timing belt slipped? Are there any marks on timing belt, crankshaft and camshaft pulleys so that I can check if timing belt has skipped a tooth?
I have tested the O2 sensor again and it looks like it's working properly. It goes from 0 to 0.9v and it responsive to heat input. Maybe I didn't heat it enough the first time
I was thinking that maybe timing belt has jumped so I checked that and all was fine so I have pulled the plug and called the mechanic to come pick up the car because I don't have a garage and all the tools neded. He then replaced the belts and all the stuff and told me that timing was little out, like belt has jumped one tooth and that everything is fine now and that they started the car and that it is running normal. He then called me that he made a test run and that engine is still running rough and that he has no idea why because everything looks fine and compression is ok. He told me that he gets a error message on diagnostic tool, something like random cylinder misfire and that they will pull the head down and inspect the engine (I have no idea why because I am 99% sure that engine is fine). I have not heard from him since but my guess is that something electrical related is wrong with the car, something like O2 sensor, ecu, crankshaft sensor or something like that and that it messes with the timing or the fueling.
burrellbloke
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