Low Boost
 

I have a 2008 SS Automatic and my boost gauge goes to about 7psi at full throttle. I have 127k on the car. I replaced the plugs at 112k I added a K&N air filter at 115k. After I bought a pickup last year I haven’t driven the SS much until a month ago and want it to be my daily driver. It doesn’t seem to have the power it did when I got it over two years ago. I would like to add a tune but I am a bit shy to use the HP tuner as I don’t want to mess up my engine with installing the incorrect parameters. Any ideas appreciated.

Well, you should figure out why the boost is low before you think about tuning. Check to see if there are any OBD2 (CEL) codes. Post what you find out here, just codes, not descriptions.

I disconnected the upper Map sensor the other day, as a test. Boost was limited to about 10 psi(if memory serves, which it often does not). But there are many possibilities.

Sitting for an extended time in the PNW invites varmints to nest under the hood.

I did have a couple of check engine lights come on but only when I used the remote starter in cold weather. They were for an engine miss otherwise no cel. I will check under the hood and the air cleaner. I have a K&N filter and sprayed it with oil sparingly could it still have affected the maf?

Oil on the filter isn't your problem.
127K on engine with a code for an engine miss is more than likely the low boost problem.

Have you checked for codes recently?

Checked for codes, none.

Check for boost/vacuum leaks, here is a link to a homemade tester. https://www.cobaltss.net/forums/how-...ss-lnf-223319/

You could also check your bypass valve, inspect the rubber diaphragm. https://www.chevyhhr.net/forums/ss-s...s-valve-44235/

So, does that mean a non-tuned SS should only boost to about 10 PSI?

I thought it was closer to 14-15, so I was a little concerned when Torque Pro shows me getting up to about 12. I am planning to get the sensors and a tuned PCM from ZZP, but (like the OP) I would like to be sure I don't have issues first.

Casa.
Stock boost for the SS can vary. Depends on air quality, altitude, etc. 14lbs. would be something you'd see around sea level (mine and your's location)
Folks in the higher altitudes may see in the 17-18lb. range.

Before my GM upgrade, I saw consistent 14's at WOT. With the upgrade it now hits 19lbs.