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6

The fact that you can smell fuel in the exhaust is a strong indication that the engine is running rich. This means that there is more fuel than required by the engine. There are many things which could cause this and the sensible course of action would involve hooking the engine computer to a scan tool to retrieve data about fuel trims, and O2 sensor ...


6

Your data logs tell me the following: Fuel trims are fine Here are some plots I generated from your data for both short-term and long-term fuel trims. The plot above (Bank 1 STFT vs Bank 2 STFT) show that there is no bank imbalance and most of the data points hover around zero STFT correction, which tells me that feedback from the O2 sensors is ...


5

Not familiar with your vehicle/engine specifically, but familiar with carbed engines in general. I would think the #1 thing to look at would be the choke. Pumping before starting a carb vehicle is normal. It gives it a squirt of fuel and sets the choke. The low RPM indicates that the high idle is not set, which likely means the choke is not set also. ...


4

First of all, the 5.3l engine (could be all of the Vortec LS engines, don't know) is thirsty. It drinks a bit of oil. Be aware you could be looking at up to 2 quarts between oil changes. I don't know exactly what the issue is, but it does have a bit of an oil control issue whether it has to do with leakage or burning. My '06 is this way. It has never ran bad ...


3

Sounds like a possible evaporative system issue involving the purge valves that vent fuel vapor from the gas tank. If the OBDII -on board diagnostic code that triggers the check engine light is P0440 then that is the issue. If the purge valve remains open for too long it will eventually damage the catalytic converters by sending too much unburnt fuel ...


1

Fuel, Air and spark in the right amounts and at the right times are what makes an engine purr. In your car there is an engine computer that controls these things (unless you are talking pre 1983 or so...) Generally problems involving fuel will set an OnBoard Diagnostics (OBD) code. Air issues are not all that common, and generally come from a totally ...


1

O2 sensors are interesting critters to diagnose. The ones at the upstream side of the Cats are the ones that send data to the ECM module continuously for keeping the air/fuel ratios optimum. The downstream O2 sensors for the most part do absolutely nothing throughout their service life. Their purpose is to monitor the condition of the Cats. If the Cats are ...



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