rough idle after boost/ low boost reading

[jaydubya87]

Ok guys I'm new to the site, and relatively new to msp's.
I've got an 03.5 msp, only mods are cai, samco upper intercooler hose, aluminum intercooler (stock location), and 3in. Turbo back exhaust. I'm having an issue, where after I've had it in boost it wants to idle really rough. Also during boost, the turbo spool seems a lot louder than normal, and instead of the" turkey gobbler" , I get a really soft bov sound. My vacuum at idle is 18hg, and no matter what I never get over 4.5 psi boost range. I've looked all over for leaks, and the wastegate seems ok (tried to blow in the vacuum line). I replaced the bypass valve already. Any ideas?

 

[jaydubya87]

Currently checking exhaust manifold and gasket. ... no leaks found so far, but about to smoke it.

 

[hornsfan10609]

That is definitely a boost/vac leak

 

[jaydubya87]

That is definitely a boost/vac leak

That's what I keep going back to, but I've tried pile checked all vacuum lines, at least that I know of. What are the common spots for vacuum leaks on the cars?

 

[hornsfan10609]

Vac lines, wastegate actuator, charge pipes, nipple for the BPV on the hot pipe if you have the stock plastic piping, exhaust mani gasket, intake mani/TB gaskets, TB itself in some rare cases, injector seals, leaking bypass valve, dirty MAF, etc.

 

[jaydubya87]

Checked all vac lines, had a code p0421, found out the exhaust manifold bolts were backing out So replaced gasket and all hardware..... new Bpv, wastegate seems fine, can't blow into it ya know. Gonna redo all the chargeable connections just to be safe and update. The weird part is no cel after replacing exhaust mani gasket....

 

[Mazda Pro]

im just throwing this in the mix since you mention bolts backing out on my wastegate the 2 bolts tend to get loose often and i had some lag issues. i could be wrong but check the throttle body postion sensor see if its working properly since your saying no sight of vac leak.