F20A 's service schedule should incl checking throttle*sensor 's wear

every 60,000 km ; *'s resistance betw the 2 pins connected to yellow+white & red+black wires ( on *'s plug ) ↑ with wear ( as the electrical c
ontact areas ↓, the ampere flowing through ↓, so resistance ↑ ). A usable * ( @ rest ) can have just 411 ohm but a worn * ( ca using idle rpm to fluctuate betw 1400 & 600 ) can have 1110 ohm. ECU interp rets this higher resistance as throttle plate having turned >20º, & so injects more petrol, so (i) spark plugs foul (ii) bottom of the idle air s crew ( on throttle body ) gets much soot, so less & less air can flow past, so idle rpm keeps dropping. Meters' panel does not show, & very few users connect a volt meter to, O2 s ensor's output voltage ( -ve during idling, if sensor is not hot enough ), so nearly no user can notice too much petrol is injected.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.