Have a 2008 1.3ltr yaris with 100k on clock.
When cold the car runs like a dream until about 10 - 15mins into the trip, once the car has warmed up.
At first I will feel slight misfires which gradually get worse. Going up small inclines may mean changing it back a gear.
As it gets worse you will be pushing harder on the accelerator to try and maintain speed and will eventually need to pull over as the car won't want to go or even idle.
Very rarely I get a check engine light and the car smells of fuel. Otherwise I get no codes on the scan tool.
So, I have thrown parts at it under the guidance of a mechanic mate but we haven't been able to put our finger on the issue.
Have changed spark plugs, swapped the coils packs from a working Yaris, put in a new O2 sensor, put in new in-tank fuel pump and filter, and put in a new crank angle sensor. None of it has changed the issue.
What do you think?