sluggish truck, 4 codes, HELP!

[nperrells]

Hello everyone thank you for taking the time to read this.

I have a 2001 Silverado 1500 Z71. A couple days ago, I noticed the truck running kind of crappy (stumbles while accelerating, choppy idle while stopped) and suddenly while driving I noticed the CEL flashing at me. Before I had time to even slow down, it had turned off. Today I hooked up the code reader and received 4 codes.

 

They are: --- P0300 multiple cylinder misfire, --- P0151 O2 sensor low voltage bank 2 sensor 1, --- P0174 system 2 lean bank 2, --- P1153 fuel control shifted lean.

 

I recently installed all new oxygen sensors, so I am at a loss as to why I'd be getting codes related to them. Any help or advice would be greatly appreciated!

Thanks, Nick

 

PS. I was reading a few different topics related to the P0300 code and how it is a broad code, and any number of problems could have caused it - so, I hope the other codes might help (possibly related?)

[newdude]

Intake gasket leaks have been known to do some funky things on the LS engines. Worst case, you have a converter issue.

[007matman]

How'd it run immediately after replacing them?

 

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[nperrells]

How'd it run immediately after replacing them?

 

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I replaced the sensors about six months ago and haven't had any issues until now

[007matman]

How's the condition of the throttle body and the MAFS? Did you try cleaning it?

 

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[Motor City Rick]

By the way, how does the truck run when your under full throttle, ...does it slightly or greatly improve???

 

I mostly agree with 15HDriver, you have an air leak on the bank 2 side (passenger side).

 

As for a convertor issue (torque or catalytic???), ....how does that effect your existing codes??? It doesn't !!!

 

"If" your skilled, take a can of carb spray and do intermittent 1 second blasts (no more) on the plenum, spray the intake gasket to cylinder head area, plenum areas, throttle body flange gasket, ...check / carefully inspect /spray "ALL" vacuum lines coming off the intake manifold. Also, follow 007matman idea cleaning the MAF with the "proper" MAF cleaner, not carb spray. Check / clean throttle plate / idle air port for any build up. Another thing most techs don't do is take the soft handle end of a hammer or a soft rubber mallet and "lightly tap" on the MAF when it's warm. If the more stumbles or stalls during the tapping phase, replace the MAF before a complete failure occurs.

 

Remember you have a 16 year old truck, I have replaced many of my vacuum lines on my 2001 Sonoma. ...and plenum gaskets do fail at that age.

 

When you stated the codes with everything being lean, the carb spray will do a temporary fuel enrichment and should smooth out the motor as long as you spray in that area. Listen for any hissing noise that might give you a clue when spraying short bursts. Don't be tempted to replace spark plugs or ignition parts. Plugs will misfire when very lean.

[nperrells]

Thanks for the replies I am going to revisit the truck tomorrow morning, I'll update then.

[Swimmer8366]

Sounds to me like every one hit this one on the head. Intake problems

 

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[nperrells]

I cleaned the MAF with the proper cleaner. Honestly everything I've seen looks clean/ no build up. While the truck was running I sprayed carb cleaner around the intake and didn't notice any hissing or anything else obvious. While idling, it still sounds like it's in the the verge of dying. I checked all the O2 sensors under the truck. None of them looked like they been burned or disconnected.

Any other tips or ideas are appreciated. Thanks.

 

@ motor city rick

The truck did seem to be running better/more "normal" under medium-high throttle. Would you suggest looking more into the gaskets and vacuum lines to identify the problem? Thanks

[Motor City Rick]

_{Did the motor idle change at all when doing the 1 second spurts of carb spray???}

_{Did you spray EVERY vacuum fitting, plenum / throttle body / EGR base gaskets ???}

 

 

_{What rpm's is the motor idling at, is it steady???}

 

 

_{Does the exhaust have a sweet smell, rich / rotten eggs smell or seems normal???}

 

_{Put you hand by the tailpipe, does the exhaust gas seem to have an even flow or in pulses???}

_{Do you feel a "steady miss" at idle or nothing consistent???}

 

_{Did / do you have a scan tool that displays the engine data??? I need the O2 sensor, #1 readings from Banks 1 and 2.}

_{Are the O2 sensors oscillating from .100 to .900 of a volt about 1 time a second or faster???}

 

_{How does the motor run at 2500 rpm's in Park / neutral, brakes on.}

_{With the motor running at 2500, has any of the O2 readings changed?? Did the motor smooth out somewhat???}

 

_{Lightly rap on the metal portion of the EGR valve with a small rubber mallet or small blunt object. Did the idle quality change???}

 

_{Did you do the rap test on the MAF when warm??? Did anything change there??? Do same procedure for TPS.}

 

_{If you have an automatic, do a brake torque to the maximum torque limits, did the motor smooth out after going above idle???}

_{If you have a stick, you are going to do full throttle runs to see if the motor smooth's out above idle under heavy load.}

 

_{As a "Hail Mary" action, disconnect the engine coolant sensor (which will log a coolant sensor code) to increase the air / fuel much richer. In addition, disconnect either the vacuum line / electrical connector (electrical connector type will log an engine code) to the fuel pressure regulator on the fuel rail which will add additional richness. Did the idle quality improve???}

_{After these actions, record "old" codes and clear them all.}

_{Does the motor run better cold at idle???}

_{I need "all" these questions answered for a much better diagnosis.}

 

[sefiroxx]

Failing IAC would create a lean condition as the low rpm tells the pcm to cut fuel

 

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