Currently have a 2009 Mazda 3 with the 2.3L engine and auto trans. It use to have code P2177,P2096,P0137. Cleared them. P2177 returns almost instantly. Cleaned M.A.F and new air filter. Checked O2 wiring which appears good. Fuel trims at idle are STFT +2,-2. LTFT is always +20.3. No obvoius vacuum leaks. Checked with propane and spray cleaner. Fuel Mileage awful, 93miles to a half tank. Did reset fuel trims (batt neg. unhook). No change after idle time. Car is salvage with 27,000 miles. It was hit in the right rear, lightly. I do have copies of the pids and freeze frame on the P2177. Thanks.
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Hello and good evening. To have that fuel trim instantly run to +20 and reset the code, means that something is making this computer see a very lean condition. It is dumping fuel into the engine and that is where all the other symptoms are from. The areas that are most likely causing the issue are Coolant temp, mass air flow, air/fuel ratio sensor, or naturally vacuum leaks, unless we lost a ground to the computer or something along those lines. Can you upload the freeze frame data for me, and I'll see if there are any clues there. This computer is seeing an unchanging lean condition. Let me see the data you found and we'll try to figure a plan of attack.
Your JA Expert,