Hi there, My 2007 prius has been idling very roughly recently. It seems to be every time the petrol engine kicks in when the main battery is low and charging. A few weeks back, the malfunction indicator light came on and i took it to the dealer. They said my spark plugs had a lot of carbon build up on them so they cleaned them up and put them back in. Also it was missfiring from time to time. The light went away but it is still idling rough if not rougher then before they cleaned the spark plugs. Its not just like that in the morning. Even if my car has been sitting in 40 degree celsius heat all day it still idles like that. They recommended I use better quallity fuel. I used to use E10 but when I was doing long drives, i filled up with normal unleded. I havent used E10 since then. It never had the rough idle problem when I was using E10 so I am curious to think my car may not like normal unleded. The fuel quality here in Brisbane Australia isnt known for its poor quallity. I'm not sure what to do next. People have recommeded for me to use Wynns Spitfire fuel treatment to keep the spark plugs and injectors clean. What are your views on this? I am interested to hear peoples opinions.Do you think the fuel treatment would make any difference? Has it helped anyone with simular problems?
I agree that the DTC are needed. That will show whether all four cylinders have a misfire, or only one. The odometer reading is an important fact to provide. I question the idea of cleaning the iridium spark plugs. If the plugs had a problem, they should have been replaced. What is the "malfunction indicator light"? Are you referring to the check engine light (amber color, looks like a small engine?) If you can upload a sound recording of the engine rough idle, that might be helpful.
E10 fuel although it gives lower MPG figures does help keep the engine clean including the injectors . I agree with Patrick the plugs should have been replaced, But dependent on millage it is possible the throttle body and MAF (mass airflow sensor) should be cleaned. John (Britprius).
The warning light that came on was orange and looked like an engine. It only came up on the main dashboard not on the screen. My car has done 79000 km. roughly 49000 miles. I dont know why they didnt replace the spark plugs. I have questioned that recently too. I just realised toyota never actually gave me the DTC code for the warning light. Another thing I should have asked for when I got the car back. Its due in to toyota for the stearing shaft recall next week so I might question it then.
ok update on engine idle guys. Out of curiosity i filled up with e10 fuel recently to see if that would make any difference and since then, the rough idle went away. running very nicely now. before i filled up with fuel last, I also put in some Wynns spitfire fuel treatment and that didnt seem to make much of a difference whilst it was running on unledded. so i guess the E10 fuel has fixed the problem with the rough idle. I think ill be filling up with that from now on instead of regular unledded. Thanks for all your help folks
