2011 Vitz engine vibrates and shuts off on ac

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2011 Vitz engine vibrates and shuts off on ac

Hey everyone,

I have a 2011 Vitz that’s been burning a lot of oil. After an engine overhaul at 100,000 km with slightly larger pistons, it runs fine without AC, but when I use the AC in D gear and stop, the engine vibrates and shuts off. I’ve checked everything—coils, spark plugs, fuel pressure—and found a noisy catalytic converter. I bypassed it, but the issue persists, and I’m seeing a high LTFT of 15% with no error codes. Looking for expert advice. Thanks!

Ahsan asked on 17 Oct 2024 10:58:47 am

2 Answers

131 views |

Haseeb Khalid - on 17 Oct 2024 11:05:59 am

If everything checks out—good compression, fuel pressure, ignition, no error codes, a working VVTi, and a solid gearbox—take a look at the throttle body. Those electric throttle motors can weaken over time, which might cause slow responses and idling problems, especially when the AC is on.

Also, a high LTFT means the car is running lean, so it’s adding extra fuel. Id address that issue first before moving on to anything else.