Anybody ever heard of fuel trims running opposite of each other and almost fixed. Mainly under 2k rpm. -20.31 +31.81. seems to do it more when cold, could it be bad o2 sensors especially with o2 sensor heaters. Unsure what it could be besides that. Reading funny and throwing the engine out of wack. Also possibly a clog in the fuel injectors, with large amounts of throttle it seems to go pass it and runs good but as soon as you let off it run poor again.
Fuel trims oppsite
- Thread starter Doriken
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07GtS197
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Which is short term and which is long term? It looks like it’s mainly adding fuel, possibly from a vacuum leak.
Mustang5L5
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I'd need to see more data from the LT and ST fuel trims.
Vac leak and O2 sensors would be my primary suspects but would need to stare at the trims a bit to help decide which.
Vac leak and O2 sensors would be my primary suspects but would need to stare at the trims a bit to help decide which.
Reading opposite like that typically means they are plugged in to the wrong connector. The harness is probably swapped bank to bank.
They are both short term fuel trims, just bank 1 and 2. I just found a vacuum hose the other day that fell apart in my hands, seemed to help but didn't fully solve. What other vacuum lines besides the on to the charcoal canister and all the ones on top of the motor would there be.
07GtS197
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If bank 1 is negative and bank 2 is positive then the o2 sensors are switched like lwarrior said.
Mustang5L5
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What are your o2 sensors themselves reading. Is your scanner able to plot them in a graph?
