Rough idle/ shuddering in idle.

[iboughtatahoe23]

Lol. Mine is slow too just a little bit faster than a Tahoe. I would definitely run E85 if I were you.

I really thought my Tahoe was gonna be fast asf when I got it idk why

 

[iboughtatahoe23]

OEM plugs and wires will do wonders for you. Start with those first! I had the same issue. I was having shudders to the point that I thought the torque converter was going bad. The dealership told me my plugs were good ( without looking at them) and wanted to sell me a transmission. I went elsewhere to have the plugs and wires changed. The plugs were bad! The electrodes were worn away on a couple of them. The truck has driven like a dream since then. No more shudders. Like you, before my plugs were changed, e85 seemed to make it shudder less. Nonetheles, stop chasing this and get those plugs. At your mileage, you need them anyway. OEM only!

Heard! Ill be ordering plugs and wires next… I just wasn’t sure bc I haven’t had any codes for spark plugs (usually I hear bank 1 will run too lean)

 

[iamdub]

So keep using premium? Seems to last longer. But I didn’t notice the shuttering happening more until after I started using premium. Which makes me want to use e85 again

If you're okay with the price of premium, then you're prime for E85. Roughly calculating, E85 will use 25-30% more fuel than non-ethanol fuel, so your MPG will suffer 25%-30%. If the price of E85 is 25%-30% cheaper than premium, then you're breaking even or coming out ahead. Talk about a life hack!

The thing is, the fuel labeled "E85" are often not actually 85% ethanol. In some places, it is. In my parts, it averages 60%. So, I wouldn't need the price of E85 to be quite that ~30% lower than premium to break even. Maybe only 25% less to throw out a figure. Even if you don't break even or better, it's okay cuz the fact that it's cleaning your fuel system and combustion chambers has value. So, enjoy the cheap gas and ignore the MPG.

If you have easy access to E85, run it for a few tankfuls and see if there's any difference. When your tank gets down to around 1/4 or so, dump a can of Berryman's B12 in it and drive it down to 1/8ish and refuel. Do this as often as you want.

If you wanna know the actual ethanol content of the ethanol fuel you're getting, you can test it with something like this: https://fuel-it.com/products/ethanol-content-tester-1

I use this one (their older version) almost every tankful to test my actual alcohol content to compare to what the alcohol sensor I recently installed on my Tahoe is reporting.

 

[iamdub]

Actually, since E85 burns cleaner (less carbon deposit buildup) in the long run, it might be ok if the E85 is only 25% less than 93. Your call.
Long story short: use more E85 as your wallet allows.
(Considering doing the same myself.)

I wasn't gonna get that deep into the maths, at least, not right outta the gate. But, yes, the benefits have value and I agree that it would still be worth it even if it wasn't a wash, financially. There's also the fact that the "E85" at the pump might not actually be 85%. Didn't wanna scare him off by dumping all the info at once. I think he's still with us.

 

[Onlyone]

If you buy plugs, check the gaps. They say you don’t have to gap them but almost every one of my AC Delco plugs I bought from Rockauto were gapped at like 15-20, instead of 40. They tell you to return them and purchase new ones but that might take a while, with how many are not correct.

 

[iamdub]

If you buy plugs, check the gaps. They say you don’t have to gap them but almost every one of my AC Delco plugs I bought from Rockauto were gapped at like 15-20, instead of 40. They tell you to return them and purchase new ones but that might take a while, with how many are not correct.

And BE CAREFUL when doing so. You can't check and adjust them like you would with an old school copper plug with the fat and sturdy electrode. Really, just avoid touching the electrode beyond a very light rub with the feeler gauges. DO NOT pry against the electrode to open the gap.

I'll take this opportunity to say that I've never had an NGK plug not gapped at its advertised spec.

 

[Onlyone]

And BE CAREFUL when doing so. You can't check and adjust them like you would with an old school copper plug with the fat and sturdy electrode. Really, just avoid touching the electrode beyond a very light rub with the feeler gauges. DO NOT pry against the electrode to open the gap.

I'll take this opportunity to say that I've never had an NGK plug not gapped at its advertised spec.

Yep. just lift up on the tip lightly until you get it where you need it. It’s not hard to bend it.

 

[Dustin Jackson]

I really thought my Tahoe was gonna be fast asf when I got it idk why

Tahoes are one of the most heavy vehicles on the road, and slow as balls because of it but once they get up to speed its like riding on a cloud and that's where they shine.

The nearest freeway onramp near my house is a 20mph cork skrew onramp and I nearly get ran off the road every time I need to use the freeway because I have like less than 1 football field to get from 20mph to 70mph merging speed after the cork screw and sometimes the semi trucks don't have room to move over for me.

 

[Marky Dissod]

wasn't gonna get that deep into the maths, at least, not right outta the gate.
But, yes, the benefits have value and I agree that it would still be worth it even if it wasn't a wash, financially.

If the engine lasts 20% longer, you're coming out ahead.

There's also the fact that the "E85" at the pump might not actually be 85%.

It almost never is. It's somewhere between E51 & E83, depending on where in the country, as well as when in the year; ethanol will never start up or warm up an engine as well as gasoline.

 

[donjetman]

We had a 2002 flex fuel surburban and when I used E85 it was hard starting and I could tell the starter and battery wouldn't last near as long so I only occasionally ran it.