Rough ride at low rpms with new CAI and exhaust

[strestDude]

I know this isn't a new topic but I'll ask anyway. I've searched the threads and found many answers. Here's my situation.

2010 Camaro (with 13k miles on it) full 2SS (every option).
first I added a K&N 63-3074 Cool Air Intake - love it as it gave me more throttle response

last week I changed out the exhaust with a full cat back Flowmaster Outlaw 3″ Cat-Back for 5th Gen Camaro which includes the following (as they state it http://www.flowmastermufflers.com/?p=764 )
• Dyno Tuned For Maximum Performance
• Stainless Steel Mandrel Bent Construction
• 3″ Scavenger X-pipe
• Aggressive Outlaw Series Muffler

upon testing and driving around for a few days, I have found that at low rpm (about 1k rpm while cursing with foot off the gas), when I just slightly step on the gas to say speed up a couple MPH) it sounds like it's hitting on 4 cylinders for a second before it starts to gain. if I use WOT, it bogs for a split second before gain. I feel in my seat that I've lost HP too. my guess is that it's now in need of a tune and that it's running a little lean or something.

I bought a new SCT X4 tuner and applied the basic pre-loaded tune and nothing changed.

question: what would you try before taking it to an over priced performance shop to tune it? More fuel? different shift points? Thanks in advance. Just looking for some opinions.

[MrChrisLS3]

Check your MAF sensor. Some of the early models, 10's and 11's had some MAF sensors that are considered "weak". See if it is just a number, or has a letter in front of the number, the lettered ones are the "strong" sensors. It seems the weak sensors cause issues with cai's.

Double check the installation of the exhaust for leaks. There's nothing about a catback that is going to change the performance of the car noticeably. It is the cats that create the first and largest restriction in the system. However, if there are leaks, it can effect the downstream o2 sensors.

[strestDude]

Thanks MrChris. I'll check that. I appreciate the feedback.

[PalmerGA]

Originally Posted by strestDude

I have found that at low rpm (about 1k rpm while cursing with foot off the gas), when I just slightly step on the gas to say speed up a couple MPH) it sounds like it's hitting on 4 cylinders for a second before it starts to gain. if I use WOT, it bogs for a split second before gain.

Is your car an automatic? Sounds like typical AFM behavior to me.

[CCMADONNA]

yeah, AFM is prbly the culprit.
Get it tuned out or get a Range AFM Delete Module.

[strestDude]

thanks everyone who answered. I've checked the MAF and it's number is K15. the car is an automatic and it's getting even more noticeable. I have an SCT X4 tuner. is there something I can set there? BTW, I ordered a new one from GM and it also is a K15. I didn't put it in until I checked with you guys.

[JusticePete]

The SCT tune was created for a stock vehicle. your Camaro is no longer stock. looks like you'll be headed to an taking it to an over priced performance shop to tune it ;-)

A CAI and exhaust shouldn't require a tune. While a custom tune will optimize your gains, it should run fine on the factory tune. You have no codes or CELs showing?

[strestDude]

OK, got it sorted. so I ordered a new MAF sensor for $86 and replaced the original (with same dang number) and nothing. finally got it to the shop so they could look for a leak or o2 sensor being unplugged. nothing there either. one of the techs told me to turn off the DOD (dropping cylinders automatically to save fuel). I took it home, hooked up the SCT Tuner, turned off the DOD and wham, all good. granted, fuel economy may take a hit but who cares right? I only drive it on weekends and only if its sunny. thank you all for your insight. one for the books I guess.

[strestDude]

no, it never showed any errors. just he hesitation. found that the slight increase (decrease pressure) in air flow from the CAI and exhaust fooled the DOD into thinking it was cruising while letting off the gas for a few seconds. this in turn started dropping some of the fuel/spark distribution until I put my foot into it. easy fix with the tuner though.

[christianchevell]

Just what I was going to recommend. Many buy a range afm disable device without tuning.

[GodWentPunk]

How do you like your Outlaws.. Are they really loud when just cruising???

joe...

[PalmerGA]

Originally Posted by PalmerGA

Is your car an automatic? Sounds like typical AFM behavior to me.

Ding-ding-ding-ding!

Originally Posted by strestDude

I took it home, hooked up the SCT Tuner, turned off the DOD and wham, all good. granted, fuel economy may take a hit but who cares right?

That's great. And I doubt you will even notice any mpg drop. A 4K pound car needs an engine running at maximum capability all the time to perform at top efficiency. My opinion is, dropping half the cylinders is not practical UNLESS you are driving on a flat smooth road with no headwind and perfect weather conditions. Otherwise, you are lugging the engine in 4 cylinder mode. Plus switching back and forth from 4 to 8 to 4, etc. is maddening.

[strestDude]

Originally Posted by GodWentPunk

How do you like your Outlaws.. Are they really loud when just cruising???

joe...

Hey Joe, sorry for the late reply. the performance shop put on Super 10's and not Super 44's that I ordered. it's pretty loud. inside, when pushing on the gas it just drowns out the stereo on about 15 but no overwhelming. it's great with the windows down and rumbling. it starts up at about 86-90db (meter on phone) outside and idles about 80-82db. inside it's about 10 less. if you're not worried about it being quiet it's great but the 44's are better for a daily driver.

[qcman]

Seeing as how you bought the SCTX4 you should hit up Dynosteve on here and get a proper custom tune for your car. It will make a night and day difference and cost very little. The trans tuning alone is worth the tiny cost incurred.

My L99 is nasty now...