Rough idle

[carguy75]

Fair point, I totally understand. Despite fueling up at Costco, to be honest I do it for mainly for the 4% CB and the convenience. I get 2% on Shell with another card so when I'm near a Shell I fuel up there if I'm in the area. It really doesn't matter.

I always tell people... it's an oxymoron to penny pinch on your ride when you've spent all that money on getting it. It doesn't matter what it is... if one dished out $30K+ for a car and then goes out and penny pinches (with intent to scrape by) with walmart oil and crap fram paper filters, believe me it's a *roll eyes* moment.

But hey to each their own... I just don't get the logic with that type of people. It's like why did you even buy the car in the first place?

Anyway... good stuff.. I wish I had a Shell closer, but unfortunently it's a ways out...

I understand your point as well. I personally like Shell V-power, however I really do not buy into the "Special Gas" advertisement from any of the gas merchants. I do believe Shell have a class leading detergent package that will keep my injectors clean without needing any extra treatments, hence why I choose the Shell brand. My goal is to keep this car for as long as possible, so I will baby it.

However, I prefer BP 89 silver for my lawnmower due to it not having an ethanol in the fuel. I have also used BP 93 octane in my Genesis when I needed to fill up out of town when a Shell station was not available. I like both brands and they both seem to work well in my engines. Therefore, I am sure any top tier brand of gas will keep the fuel system clean. So use what brand you feel is best for you Genny and your wallet.

 

[Kraig Wilkinson]

I understand your point as well. I personally like Shell V-power, however I really do not buy into the "Special Gas" advertisement from any of the gas merchants. I do believe Shell have a class leading detergent package that will keep my injectors clean without needing any extra treatments, hence why I choose the Shell brand. My goal is to keep this car for as long as possible, so I will baby it.

However, I prefer BP 89 silver for my lawnmower due to it not having an ethanol in the fuel. I have also used BP 93 octane in my Genesis when I needed to fill up out of town when a Shell station was not available. I like both brands and they both seem to work well in my engines. Therefore, I am sure any top tier brand of gas will keep the fuel system clean. So use what brand you feel is best for you Genny and your wallet.

Unfortunately out here in the midwest Higher octane fuel is not that easy to get. Atleast in the small towns of 1200 people or so. I have been using 87 non-ethanol and lucas octane boost. Seems to work very well. Saturday I took her out for a nice drive. 125mph for about 10 miles . All I can say is WOW! What a nice powerful car. She idles so smooth you would think the car is not even running!!. When I first purchased the car it idled like an old small block Chevy with a very high lift long duration cam. Those rough idle days are gone. Keep the injectors clean.

 

[EdP]

However, I prefer BP 89 silver for my lawnmower due to it not having an ethanol in the fuel. I have also used BP 93 octane in my Genesis when I needed to fill up out of town when a Shell station was not available. I like both brands and they both seem to work well in my engines. Therefore, I am sure any top tier brand of gas will keep the fuel system clean. So use what brand you feel is best for you Genny and your wallet.

The ethanol free is about 50 cents more here but worth it for small engines. In my case, Shell is the same price as other gas around here and I pass the station frequently so I use it.

On the road, sometimes I get what is available. When I pass through South Carolina I always top off because it is the cheapest around. NJ is cheap and they pump it for you.

 

[Kraig Wilkinson]

The ethanol free is about 50 cents more here but worth it for small engines. In my case, Shell is the same price as other gas around here and I pass the station frequently so I use it.

On the road, sometimes I get what is available. When I pass through South Carolina I always top off because it is the cheapest around. NJ is cheap and they pump it for you.

I forgot that NJ pumps your gas!! That was one nice thing about Living in NJ. And you can get a wide variety of fuel, 87,89, 91,93,94, octane. And 104 octane near the track. I pay about 30cents more for the non ethanol fuel in SD. I believe it is worth the extra $ .

 

[carguy75]

Unfortunately out here in the midwest Higher octane fuel is not that easy to get. Atleast in the small towns of 1200 people or so. I have been using 87 non-ethanol and lucas octane boost. Seems to work very well. Saturday I took her out for a nice drive. 125mph for about 10 miles . All I can say is WOW! What a nice powerful car. She idles so smooth you would think the car is not even running!!. When I first purchased the car it idled like an old small block Chevy with a very high lift long duration cam. Those rough idle days are gone. Keep the injectors clean.

LOL. My 5.0 was idling like a old Chevy as well at the dealership before I bought it. Not smooth at all. I mentioned the rough idle to the salesman and he tried to explain it away by blaming it on the car sitting on the lot and that it needed to be driven to clean the injectors.

I guessed that it was the 87 octane that the salesman filled it up with at the nearby Racetrack on the test drive and I was right. I filled it up a week later after I purchased it with 93 Shell V-power and it felt like a new car. No rough idling with a shaky steering wheel at traffic lights. My 5.0 Genny idled so smooth that i could not tell it was running, hence why I just continued to use Shell V-power from that point on. My engine runs perfectly with 93 Shell V-power without doubt.

 

[carguy75]

The ethanol free is about 50 cents more here but worth it for small engines. In my case, Shell is the same price as other gas around here and I pass the station frequently so I use it.

On the road, sometimes I get what is available. When I pass through South Carolina I always top off because it is the cheapest around. NJ is cheap and they pump it for you.

My Briggs and Stratton lawnmower engine seems to run year after year with ethanol free 89 gas from BP that do not gum up the carburetor if left in the tank unlike the E10 blends even with storage treatments. I wish that I can find 93 octane ethanol free gas in my area for the Genesis.

 

[Kraig Wilkinson]

LOL. My 5.0 was idling like a old Chevy as well at the dealership before I bought it. Not smooth at all. I mentioned the rough idle to the salesman and he tried to explain it away by blaming it on the car sitting on the lot and that it needed to be driven to clean the injectors.

I guessed that it was the 87 octane that the salesman filled it up with at the nearby Racetrack on the test drive and I was right. I filled it up a week later after I purchased it with 93 Shell V-power and it felt like a new car. No rough idling with a shaky steering wheel at traffic lights. My 5.0 Genny idled so smooth that i could not tell it was running, hence why I just continued to use Shell V-power from that point on. My engine runs perfectly with 93 Shell V-power without doubt.

Even after the car sits for a couple weeks, the initial start up is smooth and quiet. This car loves long drives and dislikes idling. Cant imagine driving a car like the 5.0 in stop and go traffic all the time. IMO open road /highway driving is beneficial for the smooth operation of these GDI engines..

 

[skipgen]

I forgot that NJ pumps your gas!! That was one nice thing about Living in NJ. And you can get a wide variety of fuel, 87,89, 91,93,94, octane. And 104 octane near the track. I pay about 30cents more for the non ethanol fuel in SD. I believe it is worth the extra $ .

I've seen ethanol free gas on sale at some hole in the wall little towns in the Deep South, unfortunately the places that I saw it for sale were sketchy AF - I could hear banjos tuning up in the distance....

 

[carguy75]

Even after the car sits for a couple weeks, the initial start up is smooth and quiet. This car loves long drives and dislikes idling. Cant imagine driving a car like the 5.0 in stop and go traffic all the time. IMO open road /highway driving is beneficial for the smooth operation of these GDI engines..

Unfortunately, in my area my 5.0 idles a lot around town. However, it is a very smooth ride so it makes those commutes easy. Like I mentioned, the Genesis 5.0 idles so smooth that I can not tell it is running. All I need is an audio-book playing through the speakers and the commute just passes by without much fuss.

The car interior is quiet and the engine is actually very refined and smooth running when using premium gas even when it idles. Hence why I love driving this car.

 

[Kraig Wilkinson]

I've seen ethanol free gas on sale at some hole in the wall little towns in the Deep South, unfortunately the places that I saw it for sale were sketchy AF - I could hear banjos tuning up in the distance....

Stay away! Dont do it!

Unfortunately, in my area my 5.0 idles a lot around town. However, it is a very smooth ride so it makes those commutes easy. Like I mentioned, the Genesis 5.0 idles so smooth that I can not tell it is running. All I need is an audio-book playing through the speakers and the commute just passes by without much fuss.

The car is interior quiet and the engine is actually very refined and smooth running when using premium gas even when it idles. Hence why I love driving this car.

I totally agree with you Carguy75 . These cars are very refined. I still after almost 2 years of ownership cant get over how it feels at 120mph or higher. It feels very together and tight. Saturday early evening went for a nice drive. Was having a crappy day, until my 2 hour drive in the Genny! After the drive I was high as a kite! Awesome car! Keeping this one for a long time to come.

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[carguy75]

I've seen ethanol free gas on sale at some hole in the wall little towns in the Deep South, unfortunately the places that I saw it for sale were sketchy AF - I could hear banjos tuning up in the distance....

I would not trust that crap they are selling in my Genny's gas-tank. Hell the storage tanks is probably rusted through with ground water sipping into the gas. You will be getting a fuel/water blend of fuel I bet from many of those stations.

 

[TinsleyC]

Using non ethanol fuel in small engines is key. Ethanol is what eats up the rubber tubing. I bought a new weed eater about five years ago and the guy selling it told me it'll last twice as long if I just avoid ethanol. So I buy the red cans of pre-mixed fuel at Lowe's or Home Depot and it's also a lot easier than mixing my own.

 

[joegr]

... So I buy the red cans of pre-mixed fuel at Lowe's or Home Depot and it's also a lot easier than mixing my own.

Yes, that's great stuff. Walmart now sells it (different brand) as well.

 

[Markymark]

It's weird. I use nothing but top tier gas and throw in Techron of the hyundai stuff about every month. Still, every now and then I'll get a rough idle.

 

[unlock42]

I've seen ethanol free gas on sale at some hole in the wall little towns in the Deep South, unfortunately the places that I saw it for sale were sketchy AF - I could hear banjos tuning up in the distance....

Yikes! Watch out it's likely left over moonshine mixed with an abandoned well water. lol.

Stay away! Dont do it!
I totally agree with you Carguy75 . These cars are very refined. I still after almost 2 years of ownership cant get over how it feels at 120mph or higher. It feels very together and tight. Saturday early evening went for a nice drive. Was having a crappy day, until my 2 hour drive in the Genny! After the drive I was high as a kite! Awesome car! Keeping this one for a long time to come.

The Genny never fails to impress me. You're absolutely right... I could be having a crappy day, but just going on a drive riding in this well refinded cloud does wonders. Call it what you will, but it's therapeutic.

Interesting fact: So HMG (Hyundai Motor Group: Hyundai, Kia, Genesis) make their own steel for all their cars, which makes it much more rigid than other brands. Hyundai's Steel division is the largest ship manufacturer in the World. A lot of your bridges and buildings are likely used by Steel from S.Korea and no one would ever know. This is why HMG cars feel a lot more solid and not like a tin can like a honda or toyota. The rigidity of HMG cars like in the Genesis is 35%+ more rigid than even bmw and mercedes. That figure I think is even higher now. I've owned benz all my life and trust me the Genesis feels much more solid. Other brands get their metals from china... go figure.

 

[unlock42]

I understand your point as well. I personally like Shell V-power, however I really do not buy into the "Special Gas" advertisement from any of the gas merchants. I do believe Shell have a class leading detergent package that will keep my injectors clean without needing any extra treatments, hence why I choose the Shell brand. My goal is to keep this car for as long as possible, so I will baby it.

However, I prefer BP 89 silver for my lawnmower due to it not having an ethanol in the fuel. I have also used BP 93 octane in my Genesis when I needed to fill up out of town when a Shell station was not available. I like both brands and they both seem to work well in my engines. Therefore, I am sure any top tier brand of gas will keep the fuel system clean. So use what brand you feel is best for you Genny and your wallet.

Indeed. I also just thought of something...

... if I recall correctly the Genny 3.8l and 5.0l have the same compression rate of 12:1, which explains why it's happy to sip on higher octane fuel.

There's no coincidence for those who were experiencing rough idling issues, found a remedy by upping their octane. (12:1 compression, which is on the high side so it makes perfect sense.)

It's likely that their compression increased slightly higher due to the build up on the pistons; therefore, the 87 octane was reaching its limits by burning too soon, causing the rough idle.

The higher the compression the later the burn you will want (higher octane).

 

[carguy75]

Using non ethanol fuel in small engines is key. Ethanol is what eats up the rubber tubing. I bought a new weed eater about five years ago and the guy selling it told me it'll last twice as long if I just avoid ethanol. So I buy the red cans of pre-mixed fuel at Lowe's or Home Depot and it's also a lot easier than mixing my own.

I also use TruFuel 50:1 in my gas powered blower. Good stuff and premixed for simplicity. Small engines do not last long on E10 fuels no matter how well you maintain them.

 

[TinsleyC]

It's weird. I use nothing but top tier gas and throw in Techron of the hyundai stuff about every month. Still, every now and then I'll get a rough idle.

My '19 3.8 idles kinda rough, too - but it only has 4,200 miles on it. Think it'll get better?

 

[carguy75]

My '19 3.8 idles kinda rough, too - but it only has 4,200 miles on it. Think it'll get better?

No it will get worst if you do not up the octane from 87 and use gas treatments to reduce carbon build-up on the pistons. Hyundai market these engines to use 87 octane, but the high compression design of these engines really needs 91 or 93 octane to run at it best.

 

[TinsleyC]

With only 4,200 miles on it? I've barely had my first oil change.