fuel cut? bad gas?? bad tune???
 

I've been having the problem with stuttering/hiccuping/etc during acceleration. I finally decided maybe it was the fuel I was running, other people have been having the same 'no power/hesitation" issue here in my town, and they said they switched to a different filling station and the problem was solved, supposedly there is some horrible fuel in spots in my town right now...
So I did this, and within half a tank or less, my hesitation problem was gone! Until today....but this is the first time since switching fuel that I went past 4-5k. I redlined in 2nd and 3rd, and in both gears, the hesitation came back right around 5500rpms and did it til I shifted at 6500-7k.
So is this fuel cut, a bad tune by GM, or still just problems with the bad fuel I had before?

Do you have a wideband?

No I don't. I've also been wondering if a step colder plug would be a good idea for my car since I have stage 2.
But will something as small and stupid as a different o2 sensor or colder plugs cause warranty problems later?

I wouldn't touch anything just yet.

I would take it to the dealership because it sounds like you're either slightly misfiring or you're running very rich in some points of your powerband. Does your check engine light flash when it happends?

No CEL ever, not even for a second for the entire 6k miles on the car...stage 2 has been on since just under 3k miles....and I never had the problem before stage 2, but it took a while after stage 2 install for the hesitation bs to start.

I wonder if it is running a little lean/rich, and the bad fuel made it worse, and the better fuel just bandaged the problem a little.

If you are under warranty make them fix it lol. I had issues with my stuff, but it is all after market. I changed and regapped my spark plugs, cleaned all my pipes and sensors, and upped my gas to 94 instead of 93 (because sometimes it isn't quite 93) That combo fixed 85% of my problems. You need to get wideband and the interceptor or hpt scan if you want to monitor and figure this stuff out yourself. You need to know if there is knock durring the hesitation, what a/f you are at, what heat is present, etc to isolate the cause.

You know what...

I bet you it's your catalytic converter. I was just having the SAME conversation with someone w/a Stage II and he went through like 2 cats so far. I bet your cat is getting clogged but enough exhaust is going through to not throw a CEL.

The cat, huh? Ok, I'll make sure the dumb shits at the dealership check that...

With the wideband, tho, would that void parts of my warranty?

Also, talking about fuel...the best fuel they sell here is 91, so thats the best my car gets, which is probably the low/mid grade for some of you. Which shitty fuel would definitely help the cat get clogged, so that could be a definite possibility.

Wideband shouldn't void anything, it's a seperate unit than anything put on your car and is not a modification...it's a monitoring device. If they have any brains, they would know this and not even try to red flag you.

The clogged cat would be more about running richer because you're having more unburned fuel exiting your exhaust ports and traveling down your exhaust stream and eventually building up in your catalytic converter. Your engine is one big air pump, pulling air in and pushing exhaust out. If there is a blockage like a clogged cat, it's causing a major restriction of exhaust flow and creating a major amount of exhaust backpressure which will "choke" your motor when trying to climb RPMs.

The Octane / Type of Fuel you use has to deal with resistance to knock, so no matter if you were using 86 or 93, that wouldn't have anything to do with your catalytic converter being clogged.

Hmm. Well maybe rather than take it to the dealership, I should use this as my excuse to get cat-back exhaust!

But I'm sure a trip to the dealer would be a good idea. At least I have some ideas on what it is. Thanks Adam.

dude i have the same problem, no one really knows lol if tried checking plugs, maf sensor a few things.

Well if I figure it out, I'll let you know.....and same goes for you!

I guess im heading to the dealer also i mean i never threw a code and everything.. my car is not a stage 2 mine is not supercharged its a 2.4... only about 11,500 miles on my car, when i test drove it at 7K i didnt feel it but i do now. when im at about 5,500 rpms until red line. its really annoying, like a hesitation/bucking in the car. not tooo hard but you can notice it, and your exceleration is shit.

You're welcome and good luck.

Could be getting gas with water in it (Condensation from hot days and cool nights)
Try a bottle of gas line antifreeze (99 cents) to disperse the water see if the problem goes away.
The gas station you go to might also be adding water to the tanks to increase the profit margin.
The ground tanks also condensate on there own if the dont get refilled often enough the same goes for the gas tank in the car.

Yeah, I was told that if you fill a beeker with the gas from the pump and then shake it, the water will seperate so you can see how much water is in it. Where I was filling up was about half and half. The new station that I'm filling is supposed to be the best in town, gets cleaned once a week vs. once a month everywhere else, and is about 93 octane vs. the 91 everyone else has. They also have no alcohol in their fuel. I'm on my second tank since switching, so I'm sure the bad fuel should be all gone by now.

Question: isn't water remover such as Heet bad for newer cars?

After bad gas i would check the fuel filter, that will usaually cause problems at higher RPM's

^^that is a good idea that I didn't think of....I'm gonna do that today

Any new updates on this? my car has been doing the same thing, and it's IRRITATING AS ALL HELL.

how hot is it there when you are experiencing this issue?

Mine is various. Sometimes it'll be in the early morning (62 degrees or so) and other times during the heat. (90+)

do you by chance run an oiled filter?

It sounds like I have a slight misfire at idle.. kinda surges up and down.. and will stutter randomly.. sometime when I give er it will choke for a seconds and go again.. frikken annoying