'98 Tahoe, P0300, P0304, P0151, P0174

[ChrisAU]

Buddy of mine brought his '98 2-door Tahoe to my shop yesterday for diagnosis. I pulled 4 codes: P0300, P0304, P0151, & P0174. He says its running rough, drinking gas, and will blow some black smoke and miss badly if you floor it. I suggested replacing the pass side O2 sensor, clearing the codes, and going from there.

P0300 - General Misfire
P0304 - Misfire Cylinder #4
P0151 - Oxygen O2 Sensor Low Voltage (Bank2, Sensor1)
P0174 - System Too Lean (Bank 2)

I'm thinking that O2 sensor has taken a dump and the lean condition caused by that has started fouling plugs...thoughts?

 

[Darkrider]

Buddy of mine brought his '98 2-door Tahoe to my shop yesterday for diagnosis. I pulled 4 codes: P0300, P0304, P0151, & P0174. He says its running rough, drinking gas, and will blow some black smoke and miss badly if you floor it. I suggested replacing the pass side O2 sensor, clearing the codes, and going from there.

P0300 - General Misfire
P0304 - Misfire Cylinder #4
P0151 - Oxygen O2 Sensor Low Voltage (Bank2, Sensor1)
P0174 - System Too Lean (Bank 2)

I'm thinking that O2 sensor has taken a dump and the lean condition caused by that has started fouling plugs...thoughts?

From reading this i would be inclined to think the same thing, possibly coupled with some ignition problem (the misfire code)

 

[gmcyukondriver]

Buddy of mine brought his '98 2-door Tahoe to my shop yesterday for diagnosis. I pulled 4 codes: P0300, P0304, P0151, & P0174. He says its running rough, drinking gas, and will blow some black smoke and miss badly if you floor it. I suggested replacing the pass side O2 sensor, clearing the codes, and going from there.

P0300 - General Misfire
P0304 - Misfire Cylinder #4
P0151 - Oxygen O2 Sensor Low Voltage (Bank2, Sensor1)
P0174 - System Too Lean (Bank 2)

I'm thinking that O2 sensor has taken a dump and the lean condition caused by that has started fouling plugs...thoughts?

Don't you mean "rich" condition, not lean? He said it's drinking gas and blowing black smoke, which says it's getting WAY too much fuel. An over-rich condition will also start to foul plugs. I would guess it's O2 sensors. I realize it gave a code for lean condition, but that may be why it's dumping in fuel. If the O2 sensor has failed, and thinks it's running lean, it will dump more in to correct the problem, even though the engine is actually running rich.

 

[ChrisAU]

Don't you mean "rich" condition, not lean? He said it's drinking gas and blowing black smoke, which says it's getting WAY too much fuel. An over-rich condition will also start to foul plugs. I would guess it's O2 sensors. I realize it gave a code for lean condition, but that may be why it's dumping in fuel. If the O2 sensor has failed, and thinks it's running lean, it will dump more in to correct the problem, even though the engine is actually running rich.

No, see that just makes too much sense!

 

[Blind]

the o2 sensor is probably fine, it's showing you the symptoms not the cause.

All the codes sound like a vacuum leak to me. Smoke test time.

 

[great white]

Back to basics.

Pull the plugs and see what they look like.

Pop the cap and look at the rotor and pins.

 

[ChrisAU]

the o2 sensor is probably fine, it's showing you the symptoms not the cause.

All the codes sound like a vacuum leak to me. Smoke test time.

Even with it throwing a low voltage code for the bank 2 sensor?

 

[great white]

Even with it throwing a low voltage code for the bank 2 sensor?

Meter it.

 

[gmcyukondriver]

Meter it.

Where's the fun in that?

Throwing parts at a truck randomly until I fix it is my favorite game!

 

[great white]

Where's the fun in that?

Throwing parts at a truck randomly until I fix it is my favorite game!

Carry on then