Never levels back off like the OP is describing?

 

It could vary by the severity of the restriction. It will blow out the flexible part of the B pipe if left clogged too long though.

 

So what do you think the OP's problem is?

 

Can't honestly even take a guess without driving it first.

To the OP: Have someone else drive it with you in the car. See if they experience the same choppiness.

 

I've experience a simalar problem, if you want to call it that. It feels normal and then I get a kick about a second after I floor it. I figured it was just something inherent in the programing to save gas when needed, or something like that. But, that idea was purely a guess. Honestly I kinda like the kick, almost feels like VVT to me.

 

Thats a Power Enrichment (PE) delay kicking in. You are basically going from 14.7-1 (the best emissions burn for catalyst operation) to a slightly more powerful 12 or 13-1 Power Enrichment burn. When I tune an LSJ without a dyno, I start by setting PE high and dropping it down to the point where you can no longer feel in the seat where PE kicks in. It allows 100% torque when you want it without kicking it in too early and just wasting fuel.

 

Wow, thanks! Im glad that it is an actual thing and not just my motor acting crazy. I kinda thought it was something like that, but I dont know the first thing about computers controling A/F ratios. Thanks for the imput!!

 

Wow, thanks! Im glad that it is an actual thing and not just my motor acting crazy. I kinda thought it was something like that, but I dont know the first thing about computers controling A/F ratios. Thanks for the imput!!

 

This is the easiest thing to fix:

What type sparks are you using? Iridium... Platinum?

If so, your sparks are failing... It happend in mine. Its like when you WOT, you can feel it shake a little, choppy like you said. Thats exactly what mine was like a few weeks ago. I opened up the sparks and 2 of them were BLACK! 2 of them had detonated. They were still producing spark, but the node had "flowered" when it exploded lol.

Fix:

Go to O'Reillys or Auto Zone and get NGK COPPERs!!! Do not get Iridium or Platinum, because the IRS and PLATS do not get hot enough and will not produce quick spark when our SC kicks into high gear. I bought NGK COPPER plugs, but gapped them much differently than others will tell you. I gapped my plugs at 0.28! Not to small, but not to large of a gap. The smaller the gap, the quicker the spark and hotter. Our SC need the most spark because of the high RPMS and the amount of air being forced intot he engine, it needs a hot spark to light the air and fuel mixture.

Tools you need:

Flat head screw driver
Hex driver
10mm socket
Spark Plug puller
Towel
and Aint-Seize lube
and about 20 minutes...

On the top of the engine, remove the cover with the Hex driver. (There are 4 screws here.) Once removed, you will see 4 black rubbery connectors. There are also 4 bolts holding each one of the connectors in place. Take the 10mm socket wrench and remove the bolts. (Go from left to right, leaving the connectors there but bolts removed.) At the far right side of the engine, near the far right connector, you will see another bolt, holding a black tube in place... remove that bolt and move the tube out of the way. Then from left to right, pull the 4 black connectors out, showing the spark plugs. I bet you that atleast 2 of the plugs are black and the others look new. Anyways, take your plug puller and remove the sparks, left to right. When they are all removed, take your new NGK's and gap each plug to 0.28. Drop in the plugs from left to right, and tighten them in. (IMPORTANT: Use Anti-Seize lube around the threads, and DO NOT just tighten them in without doing this: Tighten them in by hand till you feel resistance. From that point, tighten each plug 1 and 1/2 more times. You want them to be secure, but not so tight that when the engine heats up, the plugs arent crushed.) Once all plugs are in, put the 4 black connectors back on, but this time going from right to left. Replace all bolts, the one holding the black tube, and the 4 spark connectors. Put the cover back on, replace Hex bolts, close the hood, and start her up! She will run perfectly! You will notice that when WOT, it will be smooth, clear, and at high RPM, from about 5000 to 6500, you will go through the top gears much quicker, due to the amount of spark being produced, and being able to burn ALL the air/fuel in the chamber! Ive noticed a 1/2 second better 1/4 mile at the track.

Good luck and hope this is all it is!

 

like I asked before. where does the rev limiter kick in.6500 or 7000. if it is 7000 you have the revflash and the problem is probably something else.like plugs.

 

I'm not sure when my revlimiter kicks in. I have only taken it up that high once, and I didn't look down when I felt it cough...

Now I have an excuse to take it up that high again, so I will get back with that info.

 

HaHa!

Yeah, the rev limiter cuts on at 7k.


That was some info I enjoyed finding out!

 

 

Check out the Zex 82003 spark plugs. I had the NGK IX's gapped at 40 like most do and my car ran like ****. I pulled the plugs to find signs that I did not like at all. I put the Zex plugs in, and the car runs a lot better. It's smoother, and pulls harder. I was getting knock with the NGK's, so the car was pulling timing. Give them a try, as a couple people on here are using them, and each one of us is swearing by them.

 

Any update?

 

Your Cat might not be completely clogged, but it could be overheating. You will experience a butt load of knock when the cat overheats or clogs. You may be able to get one or two good runs out of it, but for the next couple hours your car will hesitate and knock while going WOT.

Gut it out and drive like a man!

 

I asked that to help figure out what was wrong with the OP's car.

 

[QUOTE=TKolb325;676329

Now that I have gotten used to the car, I am getting a little harder on it, and noticing more aspects of it. And lately, I have noticed that when I accelerate hard, and use a fair amount of boost, that the acceleration is a bit choppy.

So in the end, what i'm asking is;

Is the choppy acceleration normal, or is it possibly due to:
Boost leak
Dirty injectors
Bad spark plugs
My own paranoia
[/QUOTE]


I have had experience tuning about 14 different Cobalt SS's from Stage 1- Stage 6w/methanol.

From what it sounds like, you are experiencing knock. Here are the questions you should answer:

1. Is there an Aftermarket Intake, or intake mod on the car?
2. Are you using stock spark plugs?
3. Is the pulley on the car the stock GM stageII pulley (~3.00in), or a smaller aftermarket one(~2.80in)?
4. Does it seem to lose power above 6500rpms?
5. Is the Rev Limiter set to 7,000rpms, or does the car still redline at 6,500rpms?
6. Are you using the proper gear to drop down to when accelerating?

If you answer all of those questions I may be able to help you. Your dealership will not know jack, and should not know jack about tuning your car. I used to be an aftermarket director at a dealership, and tune most of the Cobalt SS's in Arizona. I'll get back to you with a response as soon as I can. :-)