Helping out a friend here. 2008 chevrolet silverado with the 4.3L v6 175kmiles. He calls me yesterday saying his truck tried to die on him. He was pulling up to a yield sign slowing down then tries to give it gas and it acts like its going to die. He says the check engine light has been on for a while, but it has been running fine. He goes to get the codes pulled and here they are.
https://i.imgur.com/ybKmYB2.jpg

I have never seen one vehicle throw this many codes.... Initially i was thinking it could be a dirty fuel filter, but im not certain the 4.3L has one in 2008, since it appears from my research the 5.3L has one built into the fuel pump.

He mentioned his FIL has a code reader, so I recommended to him to clear the codes and see what shows back up first and go from there.

I know the knock sensors go bad on the old 5.3L but im not sure on the 4.3L, and the rest of the codes seem emissions related. He isnt in an emissions county.

I appreciate any thoughts?

Hows the battery/altnernator?

1agswitchin4lanes said:

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Hows the battery/altnernator?

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He was driving at night and i asked if the headlights dimmed and he said no, so i would assume ok. If i recall i think the battery might be new.....

weird part is he drove it home. shut it off, and fired it right back up and it seems fine. Today he drove it back to work with no issue.

Look for corrosion on the ecu connectors. Unplug. Dooosh with electric cleaner, then go over as much of the harness as you can see for damage

Did the truck shudder and act like it was going to stall while pulling up to the yield? I had a 2001 4.3 that had similar symptoms and we fixed it by replacing the camshaft positioning sensor.

TommyGun said:

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Did the truck shudder and act like it was going to stall while pulling up to the yield? I had a 2001 4.3 that had similar symptoms and we fixed it by replacing the camshaft positioning sensor.

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Pretty much exactly that. I replaced that for him about a year ago. But I see the code is there so maybe it failed again??

3rdgenAg2010 said:

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TommyGun said:

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Did the truck shudder and act like it was going to stall while pulling up to the yield? I had a 2001 4.3 that had similar symptoms and we fixed it by replacing the camshaft positioning sensor.

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Pretty much exactly that. I replaced that for him about a year ago. But I see the code is there so maybe it failed again??

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Might want to look at replacing the crankshaft sensor, as well. Also, how does the distributor look under the cap? My A/C line used to drip condensation down into the distributor when sitting at idle. After a while it would corrode the internals and I went through two before I figured out how the water was getting in there. We put a piece of insulation over the line and it wasn't an issue anymore.

Update...

Truck went into limp mode and the engine started shaking badly. He was able to make into a parking lot. But now I'm not sure what to tell him other to try to clear the codes and see if it helps but I'm not sure now...

If he's got a little money to burn I'd just take it to the dealership and pay the $100+ diagnostic fee and then report back.

(or a reputable service shop, preferably, if they'll diagnose it for you)

Crank/cam sensor, loose distributor.

Did he take it swimming? Ever? Does it pump oil from every seal and gasket? Did it have ANY work done at Meineke EVER? Does he or his neighbor have tall grass?

Those three tend to cause a bunch of codes.

Clear codes and check condition of wiring harness. A rodent ate a bit of the wiring harness to the Tundra several years ago and it threw some codes. Agmechanic repaired the harness for us.

hey guys. Sorry for the delay dang rookie status. got an update.

he cleared all of the codes and drove it the 35miles home just fine. so he decided to just drive around town until something happened. eventually it threw a code and he checked it. Just one code: P-0651

He called the local mechanic and they told him it could be a bunch of different things, and that its really hard to diagnose. They are a small town but the mechanics are honest.

Any ideas?

Wiring harness or a failing ECU.

I'd check the wiring harness for a rubbed wire or plug corrosion near the ECU and also all the fuses.

1agswitchin4lanes said:

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Wiring harness or a failing ECU.

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Yeah I'm leaning towards a wire being shorted....