Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Uk. Renault Scenic 1.6 petrol 4cyl 2002. No DTC's No misfire.
Girlfriends car and she is thinking it's slightly heavier on petrol than it used to be. Used Snap-on to check fuel trims to see if it was adding fuel. No trims PID to check under manufacturer so I checked under EOBD. Car warm. O2 closed. Stft % is reading all over the place. Pos 10 then pos 3 then neg 16 then pos 23 then neg 6. No rhyme or rhythm. Always changing very quickly. Like different reading every 1/3 of a second.
My question is: has anyone ever seen the stft change this fast?
Yes I have, first, make sure the car is in closed loop.
What are long term trims and idle and short term and idle.
What are they when driving?
If short term is going nuts while driving, check fuel supply like driving under load, also, Ive seen dirty / clogged injectors cause this issue as well.
I will do some homework on this an let ya know if come up with anything be sure to let us know what the fix was when you get to the bottom of this thanks.
try to let you know something ASAP
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