Went to the dealer for my first service( warranty documentation) , which fundamentally is an oil change/ tire rotation. It was only 4k miles on my NA but I needed my color matched lugs:wheel locks installed ( for Ce 19"s) and figured its a 2 for 1 and cost effective as well .
After getting the car back , it actually seems less peppy - I know they reset the service alert but other than that , nothing that would mess with the PCM / TCM or other electronics - I asked - its been fine and still avgs 30mpg but I chalk it up to the oil / or computer doing sonething that senses additional friction ?
Or its exactly as it was - ? anyone have any feedback on 1st service issues - I did check the engine air filter was resealed properly as they do open it to check filter / and its right/ as well the cabin filter / -so it could be that some part of the system is now recalibrating as it drives like the day i got it - I surmized overtorquing lugs - but they would need to go outside of 120 - which I have not checked - but no lights on dash - so back to square 1 - re calibrate the computer to my habits ...by driving

 

Your CX feels less peppy to you after an oil change and you're guessing it's because the engine is sensing 'additional friction'? Additional friction after an oil change? Or perhaps the lugs nuts were overtightened? Poor fuel economy because of overtightened lugs?

No and no.

Perhaps you got some bad fuel. More likely the car is performing the same and for some reason it just feels different to you.

 

I was using Costco premium gas - Im sure it varies from state to state ....so after I read your post , went to a PREMIUM gas station which is mainstream and known to cost the most $ per gallon - I was at 1/4 tank and topped it off with premium - full tank .....INSTANTLY the vehicle performed like never before - not bashing costco gas - its just a fact , there must be something to " techroline " after all ;-)
Thanks a Million my friend - great engines need great gas -

 

I thought Costco had top tier gas?

 

Well , it says " top tier " but so does " arco " and arco makes my mazda 3 run terrible , + others say " top tier "
- All i know is when i put chevron in ..night & day - big difference - but like i said Costco likely has different distributors and is possibly less consistent - i only have this one experience to go by - on my mazda 3 - cant tell the difference , and costco premium works fine , on the CX5 - its like i put in valero or circle k ?

 

Interesting. I use all kinds of gas in my '21 GTR. I can't say I have ever had a notable difference. Even between 87 and 93 octane which is supposed to markedly increase HP. I use Sams Club the most often, but also use QuikTrip, Shell, Valero, Kroger, Marathon and Texaco. I never use Chevron.

 

familiar with the car- Great choice/ value , hope Nissan didnt hammer you to hard on the mark-up - Been looking at the Dodge Ghoul ,but only making 100 , missed the order cut - but hellcat red eyes are in production for 22 with under 100k sticker w/ mark up
- the GTR has a low compression engine 9:1 and will run fine on low octane gas / my M3 has 9:1 as well and it does well on costco premium / and the CX5 has an engine that immediatly reacts to the fuel octane /quality -1:13:1 exremely high compression for gas and in europe its :
1:14 ! - which leads me to believe its possibly closer the that here as well - that has been my experience -
It could have been a " bad batch " of gas off the bottom of the tank - or who knows - but ive been grappling with this issue since the vehicle was new - theres other factors - im over 6000 ft up elevation - so if the maf was obstructed when new - i would get a check engine light .- Im running this tank of Chevron , then Im going to try Shell - then go for 1/2 tank of Costco again and see what happens - It sucks because at Costco i can get a gallon of Premium for $4.89 - 4% using Costco citi card making one gallon knocking off about 20 cents / making one gallon premium roughly $4.70 - - I go to premium gas stations /. Shell / Cheveron / Texaco ( is chevron ) / Union 76 etc ...and Im at or over $5 / gallon where I live - so on an annual basis - a big hit - hoping it was a bad batch etc and can keep using costco - no Krogers here - but there is a Frys - which also claims " top tier " never tried it

 

Costco is not necessary considered top tier fuel. They get tanks filled from various distributors depending on where in the country you are in. Not all use the same formulas. Cheron Fuel uses the same formulas pretty much everywhere in the continental USA for even the 95 and higher octanes available at only a few area's. The Techron (patented fuel additive developed by Chevron) that is used in Chevron fuels takes a few tank full of only using Chevron fuel for it to work as it was designed and I think anyone would actually notice an improvement of their engines performance levels in all aspects?
The reason some DON"T feel any difference in a MAZDA with a Skkyactiv manufactured from about 2015(late production months) to present is mainly because running around using different fuel retailers can and does mix with the actual fuel formulas to a degree effecting the how that fuel works and also the MAZDA's ECU compensate for the use of 90 and lower octane fuels which DOES reduce both the torque and HP levels of the engine . Any amazon blue tooth Chinese cheapie OBDII scanner looking at only the timing tables can show this! AS A FACT!!!! NO guessing or BUTT DYNO assumptions.

 

Your test is not really going to be conclusive. There are so many variables that will affect the outcome. Are you planning to run a specific gravity test on each one of your test fuels?

I run a pint of xylene in my full tank of fuel about every 6 months. I am not suggesting anyone else do this . But Xylene is a fuel and is sensor and CAT safe. Its just expensive to use as a straight fuel unless it is for DRAG RACING or in a sport bike. LOL.

 

I agree / just want it to run smoothly -But that is some interesting/ helpful fuel data - I am definilty suspect of the " Top Tier " sticker I see at places that are "discount" fuel - - The only reason I thought it was ....is that sticker -

/ - On my new CX5 Na 22 - drove almost a full tank in one day / city -fwy mix and tanked up at a chevron and -.( possibly redundant here ) It was a different car - this yesterday - I may just keep going chevron - and after a few tanks switch to Costco depending on circumstances -Its by no means scientific - but the experience yesterday was an eye opener - Either previous fuel was poor - or new fuel was as it should be - Thanks for the fuel tutelage - I suspected Costco was a fuel " scavenger " buying protocols similar the store products/ one week its there , next gone / - but that dosent mean its bad - however consistency in my opinion is good - when trying to isolate an issue like this , which frankly most people would ignore -windows up, music up , cell phone ringing ....hey it starts and runs and no dash lights ...keep going - but i suppose if you are in a forum like this , your vehicle is a bit more than just A to B transportation - Tanks again