Type of gasoline used

check the owners manual. if it says premium as well then run premium.

Owners manual does not say anything about what type I.e premium or regular.......

If the gas cap says premium then it's best to run premium. Car will probably run on regular but it won't run as well as it could and should. What money you "save" by buying cheaper gas you will lose in mpgs anyways.

Hello, Page 341 of the Owners' Manual (9-63) states: R ec o m m ended F u el Use premium unleaded gasoline with a posted octane rating of 91 or higher. Y ou can also use regular unleaded gasoline rated at 87 octane or higher, but the vehicle's acceleration could be slightly reduced, and a slight audible knocking noise, commonly referred to as spark knock, might be heard. If the octane is less than 87, you might notice a heavy knocking noise when you drive. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. Otherwise, you could damage the engine. If heavy knocking is heard when using gasoline rated at 87 octane or higher, the engine needs service. I hope this information helps! Christina GM Customer Service

I have owned three Yukon Denali's and have sold them for the last seven years. The horsepower ratings for your vehicle (403 HP 417lb Ft of Torque) were done with regular octane gasoline. It is perfectly okay to use 87 octane. If you do so you will notice more of a "Spark Knock". It does not affect the reliability of the vehicle, however, does slightly affect the performance. If you can economically (I know, they cost $65,000 plus) afford premium that is what you should use.

I have a 2011 GMC Denali truck with ( 12,314 Miles) and for the past couple of days my truck just shut off in the middle of me driving it....just goes dead...I dont understand why this is happeing....thee track stabilation goes on along with the engine light...then the truck shut off.....after it shut off in the middle of me driving it I try to start it and it wont start....after a few attemp the truck turn on ....I dont understand...Please Help!

I have a 2009 Yukon Denali 6.2L. A few days ago it started to rough start in the morning when it was cold. The engine RPM would go from 0 to 1000 RPM and skip and sputter or even stall . After it started it ran great. SIS light came on. I had GMC dealer service look at it . They got Code PIP4693D: Intermittent SES light on cold start due to DTC P1400 - Due to Low Fuel Volatility. Was told to switch brand of fuel and switch to 87 octain. I have been using premium because I get better gas mileage with premium ,especially when towing. Has anyone else had this problem? I do not like the answer. I do not want to get spark knock that 87 octain gas could give me when towing. I have had many GM cars/trucks with the GM LS engines and have always used high test gas without a proplem. What did GM do to screw up the cold start?? The GM Document that covers this problem is ID 2519009. The problem exists in 2009-2010 Yukons, Tahoes Escalades . All of the above GM trucks have FlexFuel engines. I would guess is that the problem is in the device that GM is using to measure the % of ethanol in the gas . http://gsi.xw.gm.com/newsi/showDoc.do?docSyskey=2519009&from=sm

Craptor what you are experiencing is from the fuel suffering phase separation due to the high level of ethanol and moisture in the fuel. If you google "ethanol phase seperation" you will see what I am referring too. Remember moisture will naturally form in the fuel tank over time due to condensation. This is what causes phase seperation. If you do a search for a "BG Products Dealer" in your area you can purchase from them a ethanol treatment kit. This kit contains a small amount of fuel injector cleaner, and a fuel dryer. (PLEASE do not confuse this with the stuff available at your local parts stores, that stuff does virtually NOTHING. We have tested every cleaner available to us and checked the results with bore scopes (basically a small camera on a stick) and none of the cleaners proved effective.) you can purchase this product and use it once a year. If your remove the ethanol pool at the bottom of your fuel tank you should find that this rectifies your problem. On a side note your dealer is incorrect, and misunderstood the information gained from your cars computer. Fuel volatility is related to octane rating (the fuels ability to resist destination while under pressure.) and the presence of water in the fuel will play a huge rule in this matter. If the fuel lid states premium fuel, that is what you should use period, end of sentence! I would change fueling stations ( GM and many other manufactures recommend the usage of "Top Tier Fuels ONLY" in their vehicles searchable as well under the title "Top Tier Fuels" these are the stations whom sell this specific blend of fuel. The previous poster stated that it was not harmfull to the vehicles engine if engine knock is present. This is 100% incorrect. Engine knock is the MOST damaging event to take place inside and engine because the fuel is igniting (detonating) before the piston has reached the top of its compression stroke, this is VERY bad. Hope this helps. I am by the way an ASE certified Master Technician,

A HUGE marketing research study, Optimized chemical mechanism for combustion, the MIT researchers deemed AKI — and more specifically, MON — to be an outdated measure of engine performance, originally designed to apply to older, carbureted engines rather than modern, fuel-injected engines. To bring the octane rating system up to date, the team considered doing away with MON, and basing engine performance solely on RON. " Virtually nothing is gained by filling up with a premium or more expensive grade of fuel than the vehicle manufacturer has recommended, the experts say. And many of the same experts explain that drivers may not lose much performance from their cars by using a lower grade of fuel than recommended by the car manufacturer. There is little difference in energy content of regular versus premium gasoline. They both contain about 111,400 British Thermal Units of energy per gallon. The price difference, however, between the fuel grades is anywhere from 20 cents to 40 cents, depending on where you live in the United States. The experts' consensus goes against the long-held belief by thousand of drivers who fill up with premium only, or on every third or fourth trip to the pump. The idea is to fill up with premium every so often to clean out the engines or rev up the performance of older engines. But according to the experts, this practice is like tossing quarters in a wishing well, since most engines are designed to operate on relatively low-octane regular unleaded gasoline."

I have yukon 2007 i cant fill gas to tank it stooped every second i should fill slowly it take time to fill

Just got the same car today. It took quite a bit to fill up the gas. So I recommend to take your time.