Rough Idle with SES light

[siml8r5]

My truck is really starting to tick me off. I recently saw a SES light. At first, I thought it was just a loose gas cap and then noticed 200-300rpm surging while at idle. The code that it's throwing is a P0174. Fuel Bank too lean. There is a code for both Fuel Bank 1 and 2. Had the fuel pump replaced which seemed to have solved the problem, and then the light came back and then the surging went from bad to worse. Now, it is surging and idling down to at least 300 RPM and running extremely rough. It shakes horribly until I give it gas and it runs fine at driving speeds...Anybody have any clues?

[00Tahoe]

I had the same problem. Surging idle when cold, got better as it warmed up. Turned out to be the intake manifold gasket. For less than $50 and 2.5hrs of your time, you can fix it. I had been chasing the problem for awhile. Threw the 174, 171, and 300 codes.

[GM-Tech]

Is this a 1988 truck or a 2002 truck? What engine. Need more info!

[siml8r5]

You know what? Last night I scanned it again just to see if it was throwing any new codes, and it is! P0134, P0135, P0171, P0174, P0300, and P1133.

 

Will Replace the O2 Sensor tonight. Sound about right?

[GM-Tech]

Will Replace the O2 Sensor tonight. Sound about right?

 

<{POST_SNAPBACK}>

 

 

 

Could be.

[00Tahoe]

I still lay odds it is the intake manifold gasket. I changed 1 oxygen sensor when I got those codes. Still got the same code for the new oxygen sensor the next day. If you feel like the oxygen sensor is the problem, buy 1 and see what happens. Those things are like $80 a piece. $37 for the intake man. gasket.

[GM-Tech]

Those things are like $80 a piece.  $37 for the intake man. gasket.

 

True, but it's 5 minutes to put in an o2 sensor and a couple hours to do the intake. Besides, the P0134, P0135 and P1133 DTCs would not be set by an intake leak. The two lean codes definitely sounds like an intake. The P0300 is a toss up.

 

It's really tough to guess at this stuff just by the codes. It's not as if the diagnostics for any of those codes says "replace the o2 sensor" or "intake gasket leaking". They just lead you to the general area. Much more diagnosis is needed to find the actual cause.

[siml8r5]

Yeah, I just bought the O2 Sensor... $71 at Napa. I have 2 mechanics here at work that agree that the O2 sensor just needs replacement. After I replace it, should I clear the computer with my scanner?

[GM-Tech]

Absolutely. Clear the codes and if the light comes back, see what has set next or still.

[siml8r5]

OK, O2 sensor has been changed and the symptoms definitley went away. Cleared the codes and everything is still off. Drove it 3 times already. How long would it take for the codes to come back?

[00Tahoe]

When it's cold and starting for the first time of the day.

[GM-Tech]

When it's cold and starting for the first time of the day.

 

Not true. Every DTC has it's own criteria that has to be met to run the test. Few are simply cold start for the first time. For instance, here's the criteria to run the P0134...

 

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Conditions for Running the DTC

 

DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300, P0401, P0404, P0405, P0410, P0440, P0442, P0446, P0452, P0453, P1120, P1125, P1220, P1221, P1258, P1404, P1415, P1416, P1514, P1515, P1516, P1517, or P1518 are not set.

 

The engine run time is more than 409 seconds.

The ignition 1 signal is between 9-18 volts.

Intrusive tests are not in progress.

The scan tool output controls are not active.

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And here's the P1133...

 

Conditions for Running the DTC

• DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300, P0401, P0404, P0405, P0410, P0440, P0442, P0446, P0452, P0453, P1120, P1125, P1220, P1221, P1258, P1404, P1415, P1416, P1514, P1515, P1516, P1517, or P1518 are not set.

 

• The engine coolant temperature (ECT) is more than 65°C (149°F).

 

• The engine run time is more than 160 seconds.

 

• The EVAP purge solenoid command is more than 0 percent.

 

• The mass air flow (MAF) is between 2-50 g/s.

 

• The engine speed is between 1,200-3,000 RPM.

 

• Vehicles without throttle-actuated control (TAC), the throttle position (TP) is more than 5 percent.

 

• Vehicles with throttle-actuated control (TAC), the throttle position (TP) indicated angle is 5 percent more than the value observed at idle.

 

• The loop status is closed.

 

• The ignition 1 signal is between 9-18 volts.

 

• The fuel tank level remaining is more than 10 percent.

 

• Intrusive tests are not in progress.

 

• The scan tool output controls are not active.