StageII07

Ive posted somthing kinda similar to this but..my car runs fine anyother time besides what im about to explain..so here it goes
when i drive and shift to second..and get on the gas..starting to go fast..excellirating through second..my car seems to feel like its shutters..like hesitating almost..revs are fine and everything else but u can feel it jerking,its really hard to explain..it feels like it dose not wanna go faster but all of a sudden theres a small burst of speed..
now yesterday i was doing this ripping through second gear and it wasnt doing the whole shuttering thing..but after i past 5500 it gave a hard shove and continued going like normal..like it felt like somthing was holding it back..and then all of a sudden what ever was holding it back snaped or let go and it picked up..anyone ever have this happen to them..i have no check engine light or anything..its weird second time ive gotten that hard shove..first time was when i was racing..this sounds noobish and might make me sound like i know nothing about cars but could this be like..a supercharger prb orr just carbon built up in my exhaust?..somthing dumb like that?

LazerSSSC

Dude i have the exact same problem that you are having i having only experienced that shoving 1 time but the hesitation and everything u explained is identical. I have had the car into my service department (i work at a dealership in canada) 3 times and they cannot figure out what my problem is.

StageII07

i havnt brought it in yet but knowing that its not even worth it..but i cant figure out what it is for the life of me?..injectors?..spark plugs???..supercharger :x?..thank god im not the only one w.this prb..lol
maybe its just how the cars built?..

LazerSSSC

ya im not too sure either.... originally they thought it was something to do witht the fuel system and they replaced my fuel pump and fuel filter and it still has the problem. did you do any mods yet?? cuz i have a gm stage 2 kit and my problem didnt start untill after i had that kit intalled in the car.

SI FTL

My car started doing the hesitation after i installed my dp in 2nd and third

StageII07

i have stage 2 and a cai thats it..its how the car came

LazerSSSC

yah for me the only other mods i have are cai and gm performance cat back exhaust. yesterday was my day off and i was driving to my buddies work after grabbing a coffee and the jerking was so hard when it really starts to pull that it ****** pushed my coffee right out of the cup holder.

Dainslaif

Try changing your CAI back to the stock one. I'd guess that's the root of your problem.

LazerSSSC

tried that.... still does the same thing so im not sure what else to do next

arkkornkid

shutters...

but seriously, I honestly don't know what it could be, I get a flat spot at 4000 rpms in second gear, I toss that up to possibly spark blow out, but I don't want to lower my plug gap any lower than 38.

Vetteman-sssc

I also have the same problem & have no mods or stage 2.

The feeling I get is like a quick sputter or kinda like a bog.
Must be common for the Cobalt SS\SC .

Its probably the GM tune they use to flash ecm,wonder if anyone with Hp tuner has this issue

Mr McCabe

I'm going to say its a GM thing. I've personally owned 3 gm's and they've all done the same thing. My 04 Cavi did it really bad to the point passengers noticed it. When I took it in GM couldn't find anything wrong. My SS/SC does it too but it's very minimal to the point I hardly notice it.

LazerSSSC

Ya mine is very drastic. If there is anyone out there with hp tuners can you please let us know if you have this issue or not.

rnjmur

This is a pretty common problem. It is due to the GM tune. The AFR jumps all over the place during moderate (non WOT or PE) acceleration. An tune to level out the AFR usual corrects the problem.

LazerSSSC

sweet thx man ill give that a shot

rnjmur

Oh thought of something else... there have been a few times where the spark dwell with the GM tune causes this issue as well.

MR.PONTIAC

Makes sense.

My SS, of which I have tried everything to make run right for over 45K miles, does the same thing.

Seeing as how mine, and likely other's cars as well, run correctly in open loop points in the direction of the tune.

So where do I get a tune? Who do I have to see? What will it cost?

Thanks!

rnjmur

You can get a tune from a performance shop or from someone with knowledge of Hptuners. As far as how much it costs, that really depends on where you go and who you have doing the tune. Prices could run from $150 - $300 dollars depending on dyno time, licensing costs and the tuner's time.

PhantomSS

qft

its more to do with the ve table since the dynamic maf/ve blend is so far apart they fight with each other. Ive had this problem before, also DFCO needs to be tuned accordingly or it will fight with it as well. The 4k bog should be more like 5600 bog because thats where the dynamic airflow hands it to the maf and it isnt a pretty transition.