Fluctuating Boost
 

I've noticed in the last two times I've driven the car that my boost is acting weird.

I normally put down about 18 psi.

now, it'll fluctuate between 10 and 15, almost "surging" between the twowhen I get on the gas.


What should I look for, for a potential cause?

RE: Fluctuating Boost
 

Boost leak maybe, the throttle boddy boot is a common source so check there first.

If you havent replaced your DV's you should at least get some 710n's too

RE: Fluctuating Boost
 

I guess I should have mentioned...

I have samco hoses (that's for the TBB, right?)
and
hybrid BOV/DVs.


Also, I found that it'll fluctuate from 10 to 15 then stay at 13.
or
it'll fluctuate 10 to 15 and go to 18 and stay there.

RE: Fluctuating Boost
 

id pressure test

RE: Fluctuating Boost
 

yup, definatly a pressure test is in need. leaks can happen in about a million places along the intake tract.

RE: Fluctuating Boost
 

great, thanks guys.

I saw that AWE sells a boost leak test kit. I'll pick that up and go from there.

Thanks.

RE: Fluctuating Boost
 

Put in the old DV's & see if the problem goes away.

I have similar problem, running giac file with samco hoses and 710N's, boost hits 20psi then drops to ten and back to 15, then up and down from so on.
and it also holds a steady 16psi sometimes after a 19 spike.
I just replaced N75 as well, and both O2 sensors, with no change. I pressure tested and can't hear any leaks.

Have you gotten your car scanned to check for fault codes? Does you car feel like it's misfiring? You could have a bad spark plug or maybe a spark plug that is gaped too large. Bad EGR sensor, O2 Sensor, Maf, fuel injector(s). Hard to tell. Get you car scanned and post of the results for us to look at.