hey guys I made a thread in the problems forum but I think I would get much better responses here.. anyways heres the story..
I have an 08 ss/tc with a Hahn intake and mPX downpipe., trifecta tuned. I was on my way to visit this hottie who lives roughly 25 mins away and noticed that my car was not hitting the normal 22psi on the highway when I gave it a little love... left her house a few hrs later and as I back up out of her driveway I noticed my CEL is on, so I baby it home.. misfires in cylinders 1-3, engine misfire, and 2 other codes. one was p0451 -history ses stored- but I believe that may be from another incident where my car wouldnt start right away after I got gas.. but the most recent code was p2187 system too lean at idle bank 1... any ideas guys? Any info would be greatly appreciated.
** Tonight I babied it around my street.. noticed that when the RPMs are like at 3 grand or higher and i press in the clutch and shift into neutral, most of the time the rpm needle would normally drop right down, but now it is dropping slowly and will stay near 2k rpms for a second before going down lower. Very frustrating having a daily driver not running good. I spoke to one of my buddies with a sick nasty tuned EVO and he said it may have something to do with the what I believe is called the primary 02 sensor, not the one in the downpipe. anyways any suggestions or ideas welcome.

** and it has been starting and Idling rough too.

 

Vacuum leak on the intake manifold will cause a lean idle. Look for obvious stuff first under the hood, cracked vac lines, boost tubing, ect.

Check for boost leaks while you are at it. Look at the vac line off the lower CP that runs up to the boost solenoid on the mani, some have a cracked off nipple or a hole rubbed in the tubing from the fan shroud.

 

I was looking earlier when it was light out, but didn't see anything broken, I'll take a better look tomorrow when it is light again.

 

There is a TSB on a lower CP bolt for the radiator support that can rub through the CP, I had to cut that off on my '08 before it rubbed through when I still had the stock CP. I think it was on the driver side, but it's been so long gone IDK for sure.

 

Ah, those boost leaks and vac leaks. Nature of the beast.

 

wow this is making me soooo mad as I can't find a leak anywhere, but it really seems like a boost leak. jacked it up checked out the intercooler and the lower pipes, as far as I can tell they are all fine. All this work when I just had back surgery 2 weeks ago!!

 

The other day while standing still and revving the car; I also notice that for a few seconds the rpms where dropping slowly and will stay near 2k rpms for a second or two before going down lower. It happened before but is very random. No cel's or anything! should I be worried ?

 

Take the charge piping completely off, examine it closely and then reinstall it. Make sure to really check those vac tubes.. A small tear of rip anywhere on them could do what your describing.

 

stupid question, how do I take the bracket off the factory upper charge pipe recall? I looked at it and theres some funky clip that I don't know how to take off.. Im going to go for a drive around the block and see how it's running. in stock mode the car should normally hold the boost at a certain level if you keep your foot planted at about 50% throttle, right? If I remember correctly, every time it would not hold boost and stay really close to 0.. Im hopping in now that it has stopped raining.

thanks for all your answers btw guys

 

stock tune will only boost to 6 psi, trifecta tune goes to around 20, but it doesnt seem right.. I didn't have a CEL but my codereader had a few misfires,, and I just cleared the history yesterday.

 

Thats not true at all. As the rpm's climb and the engine thirst for air increases, the level of boost will decrease. As long as you hold your foot at 50% throttle... Its like making your k04 turbo a seashell sized turbo (really tiny turbo) and your seeing the turbo unable to produce the cfm's necessary to force feed your thirsty car.

Try to maintain 7psi in your car when it's working well again.. you will notice that you have slowly keep increasing the throttle as the rpms climb to hold that 7psi boost.

 

As for stock tune boosting to 6psi only and trifecta to 20psi... did you run the car to redline to see the max boost? If so, dont do it again. your fuel trims should be waaaayy off. Not safe for the car, especially if they are in the positive direction since you got a Lean code.

 

Its a boost leak. Check the lower pipe really well, if you still dont see anything, check the intercooler end tanks assuming you have the stock intercooler.

 

99.9% sure it is not a boost leak issue.. I took apart all the pipes and checked the intercooler, no cracks.. did a few data logs with vince and the car was pig rich on deceleration, that may be why it was hovering at around 2K rpms when I would put the car in Neutral and like Mikko's car.. I have the exact same mods as him. I re-tuned the car and it is driving around fine now in stock mode, veeery very strange. HOWEVER, I just remembered that the night before all this happened, I went to get the same gas I always get (Shell V-power 93) and when I turned the key to start the car, it cranked for like 10 seconds before I shut it off, not wanting to damage the motor. tried a few more times and finally got it to start by pressing the gas slightly. The same thing happened to me this morning getting gas. Any Ideas guys?

 

Secret! Don't rely on your eyes alone when searching for vacuum leaks. Put you hands in there and feel/touch along the length of every pipe/hose between the intake manifold and the other end where ever it terminates. Same thing for the intake and boost tract. Feel for anything that doesn't feel right or feels spongy, etc. My vote is a vacuum leak, albiet a small one. Sounds too random for a ECM malfunction. But random enough that the problem shows itself under hot/cold cycles or movement of the hoses. Back in the day we would put a rattle can straw on a can of ether and hit each and every area that could possibly leak, with a tiny bit and wait for the RPM's to go up. I've also seen guys use a very light oil to do the same thing but in the case of very minor leaks you need somebody to watch the exhaust for the tell tale puff iof smoke. Of course this is JMHO!

 

This is going to sound weird - but also check your stock plug gaping while you are at it. I agree with the guys above you - but I also found that when I replaced my plugs in my car they had come from the factory gaped anywhere from a .046 to a 0.036. Interesting thing to note is that the OEM spark plugs don't even vary like that.

 

Check the maf sensor for oil contamination from the k&n on ur intake if u have that filter.

 

The extended crank might be an EVAP thing.

You need to do a boost leak test to find a boost leak. You can't just eyeball the chargepiping and find a boost leak. I wrote a thread on here somewhere about how to do a boost leak test. Search for it and ye shall be enlightened.

 

Pulling out the MAF now, just eyeball it for oil or should I try to clean it.. SSlow I will look up the thread as soon as I can... Having Major personal issues lately and just recently had hardcore back surgery, so it is a little hard to find time to tinker around with the car, and it doesnt help It is my only car and have to baby it everywhere now. Thanks for all the info guys

 

MAF looks good... I have been having issues now with high engine idle (P0507) and it puts the car in a limp mode.. any ideas guys?

 

Dude, that sucks. Sorry to hear. I had drop-foot last year from a pooched disc. I feel ya.

 

I don't know if u checked this yet. See ixf your map sensor is functioning if so go for a boost leak if you are not having any type of leak check ure compression if all checks good go for injector or plugs. Did u happen to get colder plugsssss. I just looked at a trifecta tuned car the other day he had the
25lbs tune and I looked at it and his map sensor was done for .... All ure code and issues u r having he
had so hopefully it's just a map sensor. I'd get a 3 bar map unless u have it already.

 

I wonder if this has ever happened to anyone else. Mine were gapped perfect at 0.035" from the factory. None were off by more than 0.001"

 

Well guys I think I may have narrowed it down to a few things that may be causing my car to run like tequilla *****. I am thinking that it may be an issue with my evap sensor, as that along with the lean Idle code are now the only ones present after I put my stock airbox on and it still has the extended crank every time I fill with gas... Unfortunately my noob self does not know where the location of the evap sensor is. I want to try unplugging it first, as I read on here somewhere that it would solve the problem, if not then I may just replace the sensor, I heard they aren't too expensive. Can anyone help me out and let me know where the sensor is and if there is any other way to test if that is the problem?

 

It's right on the front of the intake manifold. It's black and sticks up about 2 inches. Someone will surely post a photo of it. I thought I had one, but don't.