Hey guys I have a 08 cobalt SS and lately I've been having problems with it. I have a K&N cai, zzp tune, and a zzp 3" catless dp. I've been noticing that I haven't been getting the 22psi that I'm supposed to with the tune on my car and a few times while going wot in 5th gear it'll hit 20psi and it'll hesitate and then boost will drop to 0psi. I have gotten a cel from it but not everytime. I took it to autozone and they told me it was my maf sensor which I cleaned the hell out of with crc maf sensor cleaner and it's still doing the same thing and I'm not getting that 22psi anymore. Help please.

 

My 2 cents, if the code is for a MAF, and you cleaned it and it didn't work then replace the MAF.

I wouldn't think its a boost leak cause its only 5th.

 

If you haven't had ZZP adjust the tune, that's likely your problem. Just because there is a DTC for a sensor, doesn't mean the sensor is bad. This has been covered many many times.

 

Why would adjusting the tune do anything if everything I have is already tuned fort car?

 

It might be some what of a boost leak, the turbo is working pretty hard in 5th and it never hurts to test for one with some regularity.

I second the recommendation for the tune adjustment for the K&N, different times of the year call for different MAF table adjustments since there is no air straightener. But I'm not sure its directly related the the 5th gear issue. I'm assuming when you say WOT in 5th your not going WOT from like 70-80 in 5th. I can't say i've ever top out 4th around here so i'm not sure what would be requiring you to be going WOT in 5th unless youre doing a mile drag.

 

It's happened to me in 4th also and everytime I lose my boost my car goes in "limp mode" where it won't exceed 5psi and I'll just unplug my battery to clear the cel

 

Start with a boost leak test (not checking the fittings, actually put pressure on the system). Also stop pulling the battery to clear CELs, scan them to determine what code threw. Is it a flashing CEL or just solid on?

 

It's a solid cel not flashing. Idk if this helps but this all started after I got my catless dp put on but I don't think it has to do with anything. I mean the turbo spooled up faster which could've loosened a vacuum line

 

It obviously isn't tuned properly. Your fuel trims are likely skewing far enough to trigger the DTC. Anything MAF related will reduce boost.

 

But like I said my car is tuned for my K&N cai but not my catless dp, but that shouldn't matter, right?

 

Who tuned you? I'd bet its going into overboost protection

 

zzp did

 

LOL my car is doing the exact same thing. AEM cai (about 2yrs), GMS1 (about 1yr), the rest of the drivetrain is stock. Car went into limp mode, pulled the battery cable to clear codes, easy driving for the rest of the day. Next day the car felt fine so I rolled on the throttle, hit 15psi boost and the car stumbled and went right back into limp mode - 5psi max, 100hp max. The MAF code and an UNDERBOOST code. I tinkered with it as much as I could but after awhile said **** it and took it to the dealership. Extended Warranty

 

What did the dealer do to fix it?

 

I dropped it off yesterday, not fixed yet. But they called me to confirm the issue. The tech pulls the MAF code and Underboost code (can't remember the exact DTC #) with the tech 2, clears them, then test drive. Car hits 15psi, stumbles and goes right back into limp mode - 5psi and 100hp. They are going to continue dignosis tomorrow. I looked over all the piping and hose connections and nothing obvious. Like I said, GMS1 tune not HP or Trifecta so it's not a faulty tune but it does seem to be software issue. I'd guess the MAF took a ****, the tech thinks so too, he's gonna replace it tomorrow and let me know what happens. This is why I got the extended warranty. Between this, broken sunroof track (twice), air bag light (passenger seat belt retractor), stupid tire pressure sensor, and can't remember what else, it's paid for itself. I'll keep you posted.

 

Stock tune with aftermarket intake earns another

Good luck in your MAF sensor replacing endeavors gentlemen.

 

Safe to say it's not overboost protection then. Look into the maf more, clearing the codes makes it difficult to know though

 

Sounds like I need to buy a new MAF sensor then. I'm still gonna take my car to my mechanic to check for any vacuum leaks or loose lines. But yeah please keep me posted cause if it's just my MAF sensor I'll buy one from zzp right now

 

So, the issue is a cracked intercooler end tank. Not a full blown crack, just enough to loose psi at higher boost. It's a "hair-line crack" you can barely see doing a visual inspection, and even holds 7-8 psi but looses pressure during higher boost levels. Gotta love the plastic fantastic parts in these cars. Hope this helps.

 

Was it your end tank on your hot or cold side? And where was it cracked?

 

Too quick to judge :p