Had a slight misfire on cylinder one so fitted a new injector and changed the four plugs at the same time. Now it runs ok for a while and then rattles and wobbles when coming to a stop. It showed obd code P0420. If I switch it off and on again, it then runs fine for a while but then happens again. Any suggestions? Thanks guys
what was the reasoning behind changing the injector? How did you determine it was an injector fault? did you troubleshoot the misfire and/or did you get a P0301? how did the plugs look when you pulled them out? how many miles/km on the clock? how much oil burn between oil changes and at what interval?
Yes. Had p301 so I changed the coils over and spark plug looked ok but fitted a new one anyway and misfire was still there. 175,000 on the clock. oil is fine
did you do a compression test or look at fuel trims before replacing the injector? Did you do all 4 or just one injector?
Do you think engine temperature, when car is warm or cold changes anything? Or when idles you have the issue and when driving with higher rpm is working fine?
Misfires are harder to detect at higher RPMs, unless the engine is under heavy load - climbing very steep hills. A Prius specific diagnostic OBD2 unit would allow an easy diagnostic of that car. Without proper testing and test equipment, your going to be spending a lot of money in a "parts cannon", and possibly introducing new problems, creating layered issues in the car. Just my opinion......
You should've done a closer inspection of the spark plugs, if #1 was missing, the spark plug condition should confirm it. Darker blacker electrodes if running rich, white ashy burning lean - when comparing to the other three. That would confirm an injector issue without a scan tool. IMHO; take it to a professional..... Sorry.....
