Recent content by los341

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    SOLVED Please help, engine runs very poorly!

    Problem Solved! I figured out what was wrong! In my original post, I mentioned that I checked the pre-cat exhaust pressure as less than 1 PSI. When first I checked it, I had to hook it up to the O2 Sensor 1 hole (pre-cat) on each side. Since the gauge hose wasn't long enough for me to see it...
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    SOLVED Please help, engine runs very poorly!

    Hello Fless, thank you again for your suggestions. I tried pulling all 4 oxygen sensors and the engine still runs bad with near continuous misfires on bank 2, especially cylinder 6. I'm just running regular 87 octane fuel with no ethanol. Fuel pump / filter assembly is brand new and verified...
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    SOLVED Please help, engine runs very poorly!

    Hello again Marky, per your suggestion I swapped the entire bank 1 set of coils with bank 2. Unfortunately the misfires are on the same side as before. I also removed and cleaned up the engine ground strap. I also verified a good connection and measured a near-zero voltage drop between the...
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    SOLVED Please help, engine runs very poorly!

    Thanks DodDel, I'm just curious, since the engine has a single camshaft wouldn't a cam timing issue affect both banks equally? Thanks, Carl
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    SOLVED Please help, engine runs very poorly!

    Thanks rockola, I checked the fuel pressure today. It's rock solid 62psi at any rpm. Also brand new plugs and wires. I took off engine ground wire and cleaned as you said. Also checked for any voltage drop between engine and chassis. It's is practically zero in DC or AC.
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    SOLVED Please help, engine runs very poorly!

    Thanks Fless, those are some great suggestions. I'll get that information!
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    SOLVED Please help, engine runs very poorly!

    Thank you Marky, I'll try swapping coils and checking engine to chassis ground quality. Carl
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    SOLVED Please help, engine runs very poorly!

    Hello, I have a recently acquired 2005 GMC Yukon XL 1500 SLE with a 5.3L flex engine. It's been running poorly ever since I got it. I've been trying (diligently) to figure it out to no avail. I've done so many things to it and nothing has helped. I'm running out of ideas. Symptoms include...
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