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Hello,
I have an alfa romeo mito 1.4 t-jet (120PS) with A LONG TERM FUEL TRIM of -22.
Sometimes it gets to -25 and throws a P1172 code.
o2s1 is around 0.8V and o2s2 is around 0.4V at idle. I changed the o2s2 sensor and nothing happend.
Intake manifold pressure: 34 kpa
Does it stay there permanently or move up and down?
I just did a search and found "I've just noticed that your car is a JTS; upper lambda errors seem to be very common with these engines. Mostly it is just the connectors that are the problem; I believe the Dealer solution is to solder the (loom) wires to the (lambda) connector."
Getting involved in discussions because I have a lot to learn still.
I'f I'm thinking of the correct system your oxygen sensor 1 should be reading as in this image - if it's stuck on 0.8 the fuel trims will keep going negative to bring it down again and eventually throw the fault code.
Getting involved in discussions because I have a lot to learn still.