Tahoe started to run weird!

[corvette744]

Cylinder 1 -spark plug if your gonna pull it replace it-plug wire switch number 1 with next closest cylinder-if still shows code p0301 then switch coil to next cylinder as stated earlier.If code moves you know what it is.If after all those and still shows p0301 pull injector connector if it doesnt run rough it in the injector or harness.Noid light or as stated in another previous post 194 bulb watch for flashing.

 

[SnowDrifter]

Pop the plug put of cylinder 1 and see how it looks!

It's the driver's side front most. Right. Behind the alternator

Could be as simple as plugs and wires. To a piece of sediment or something got lodged in an injector. To rodent damage.

Also check your plug wired and make sure those aren't melted or cracked

Little unusual that a plug would go from nothing to presenting itself so strongly, but that's first step to check.

Don't go running out and buying parts just yet though. We're just doing a quick visual inspection.

 

[iamdub]

Put gas in it? Maybe the gauge isn't reading accurately and you're actually on fumes. That slight bit of "smoke/steam" could've been steam off the brakes. You said you noticed it when you had just come to a stop. Your location says Washington- was it wet out?

 

[hertahoe]

Pop the plug put of cylinder 1 and see how it looks!

It's the driver's side front most. Right. Behind the alternator

Could be as simple as plugs and wires. To a piece of sediment or something got lodged in an injector. To rodent damage.

Also check your plug wired and make sure those aren't melted or cracked

Little unusual that a plug would go from nothing to presenting itself so strongly, but that's first step to check.

Don't go running out and buying parts just yet though. We're just doing a quick visual inspection.

So I popped out #2 first because I wanted an easier test. It looked pretty worn. IIRC they have approx 40-50k on them and are the NGK V-power. I also smelt fuel, so something isn't burning properly. Probably best to get some plugs at the least. Then once I start to replace them, I can see if other plugs are bad or are fouled. I will go out now and look at #1. Didn't want to ask for advice and not follow it. Much appreciate all the responses! This community rocks! I need this thing to last since I will be taking it over in a few months. Have been looking at getting wife the 3.8 Duramax diesel Tahoe.

 

[hertahoe]

Put gas in it? Maybe the gauge isn't reading accurately and you're actually on fumes. That slight bit of "smoke/steam" could've been steam off the brakes. You said you noticed it when you had just come to a stop. Your location says Washington- was it wet out?

No. Had it idling a bit ago with no smoke. I don't hear any other abnormal sounds either.

 

[hertahoe]

What plugs would be best?

 

[iamdub]

What plugs would be best?

OEM or equivalent! Just be sure they are genuine. Plugs are a hot item to have been counterfeited. Basically, if they're really cheap, they're likely knock-offs. Best case, they just wear out quickly. Worst case, they fall apart and cause major engine damage.

I'm not totally sure, but I think Gen 3 and Gen 4 engines take the same plugs. I put NGK Iridiums (TR5IX) in mine when I refreshed/upgraded the engine in mid-2020. Should be good for 100K miles at least.

 

[Donal]

NGK Laser Platinum Plug Number PTR5D-10 Spark Plug is my choice. They cost more but last the longest. Save the invoice and document the mileage. they have milage warrenty. Cost around 14.oo each.​

Fill the gas tank. If you have the tools check fuel pump. Fuel pressure should go to around 48-50 psi and hold, go down 10-12 psi and hold.

 

[swathdiver]

Tech-2 time. Use OE Plugs and wires.

I paid about $6 and change each for brand new OE plugs at RockAuto recently and got a $24 rebate check from GM.

https://parts-catalog.acdelco.com/acesCat.php?

 

[corvette744]

I would follow the procedure i outlined and others first.Yes if you pull number 1 i would replace it just to see if the miss is gone.But before replacing anything else do as outlined to narrow down the failure.Switching the plug wire and or coil to the next cylinder will tell you what the problem is if its ignition.If no change pulling injector connector and seeing if it pulses is the other area.po301 is specific to number 1 cylinder find the problem in that cylinder.Is the tahoe missing at all times-warm and cold.