Hi guys. First post. Sorry if its in the wrong spot.

I have a 2006 Chevy Silverado 1500 LS Crew Cab 5.3L with the 4L60-E transmission. 4x4. I have been troubleshooting it for over a week for a misfire that I can’t find. I will post the codes below. Before I do, I’d like to explain what I’ve done so far.

I’ve put new plugs, wires, coil packs, injectors, O2 sensors, and fuel rails. My father seems to believe it could be the cam position sensor. My check engine light blinks indicating misfire. (Ignore the abs codes/O2 codes I’m not worried about those, unless it’s related.)

Here is a list of codes last time I checked after installing everything new.


Truck codes

P0300 - random misfire detected
P0053 - HO2S Heater Resistance (Bank 1, Sensor 1)
P0054 - HO2S Heater Resistance (Bank 1, Sensor 2)
P0056 - HO2S Heater Control Circuit (Bank 2, Sensor 2)
P0059 - HO2S Heater Resistance (Bank 2, Sensor 1)
P0060 - HO2S Heater Resistance (Bank 2, Sensor 2)
P0200 - Injector Circuit
P0036 - HO2S Heater Control Circuit (Bank 1, Sensor 2)
P1380 - ABS/EBCM/EB(T)CM DTC Detected/Rough Road Data Unusable


ABS DTC’s

C0035 - Right Front Tone Wheel (Subfault)

I’m at a loss with what to do next. Anything helps. Thanks guys

 

The O2 sensors have a direct influence on air/fuel mixture control. With those codes being set, the PCM can’t enter closed loop control and it’s defaulting to a slightly richer AF mixture. It shouldn’t be rich enough to cause misfiring.

The codes indicate the sensors are unplugged or there’s a power/ground supply problem. Check fuses O2A & O2B in the under hood fuse block - if good, check for battery voltage at the pink wires at O2 connectors during the first 2-3 seconds after the key is turned to the ON/RUN position. There should be enough power to light an incandescent test light grounded at the battery.

Was there any work done before the misfire started?

Are you noticing any drivability problems? Lagging/hesitation during acceleration, smelling gas, etc?

 

I do smell gas quite often and have checked the tank and feed to the tank for leaks there are none. As far as work done prior, I’m not sure. I just bought this truck recently. Had misfire when I got it. I cleaned my MAF and that did nothing as well. I can check the fuses / battery voltage tomorrow

 

Check fuel pressure when you can - it should be about 55-62 PSI and results should be as follows:

1) Key on, engine off, it shouldn’t lose more than 2 PSI in 5 minutes.

2) Engine idling, at least 55 PSI with a steady needle. Preferably the engine is up to temperature, but if it won’t run long enough to open the thermostat the result should be similar.

3) Rev to 2500 RPM & hold - pressure should hit at least 62 PSI & hold steady until the engine returns to idle.

 

update: truck started running rougher, hesitation and rpm jumps before I hit 40 and in the low rpm range (500-2k) once I hit around 40mph the hesitation and rpm jump stops and it sounds much better. The way it sounds before it hits 40mph is like something is clogged. Sounds like it unclogs at 40 and I get way more power.


Today I cleaned my MAF sensor (was pretty dirty), tomorrow morning I will clean my throttle body. I’m also going to get a fuel pressure gauge and check that as well.

 

Remove both upstream O2 sensors and test drive. If the hesitation/erratic power is resolved, the converters are breaking down & need replacement.

You can gut them as a temporary solution but make sure there’s no misfires or the new converters will be ruined as well.

 

Another update. Cleaned throttle body (very cruddy) Checked fuses. Got voltage tester and checked ohms and voltage at each injector. All function properly. Fuel pressure still reads 46 psi at idle (should be 55-62 iirc) and drops to 39-41 when shut off. Truck also stalls at 1/4 tank or less. I’m guessing there’s tons of crud in the bottom of the tank. It’s been very cold up here in Maine so admittedly I haven’t messed with it too much (also rarely driving it), until tomorrow. Tomorrow/Saturday I will do a full diagnosis on all things mentioned in this thread and give a full update. Thank you all for helping

 

I too thought I had a misfire. Local mechanic diagnosed weak fuel pump. Although I was skeptical . . . . replacing it solved issue.

 

Fuel pressure is too low. Most likely it needs a pump, but first do a thorough inspection of the wiring harness along the driver side frame rail, from the engine bay to the top of the fuel tank. Use an inspection mirror to see the top side of the harness/tank. Dirt/rocks/debris accumulate between the harness and rail over time and can eventually cause chafing/wire damage.

If no wiring damage is found, replace the pump. Note that the replacement pumps - OEM and aftermarket - often require replacing the factory electrical connectors - the new pump should have instructions for doing so.

It’s also very common for the tops of the pumps to rust out and the fuel supply fitting can break off and get stuck in the line. The replacement line is cheap so I recommend having it ready when you drop the tank.

 

I want to add to what @Gumby22 said above, and say that if you are doing this work yourself, on my 1996 C1500 rather than drop the tank to replace the fuel pump, I unbolted the bed from the frame (there are 8 or 10 bolts that hold it on), removed the tail lights and tailgate, and unbolted the fill tube, and with just one helper, we lifted the bed and walked it backwards a few feet and exposed the gas tank. That made it trivial to replace the fuel pump without dropping the tank.

If your gas tank is entirely under the bed of the truck, unbolting the bed may make the job simpler than draining and dropping the tank.