So I posted on here a couple of weeks ago and I didnt get one reply, but 340 views. So hopefully I can get some suggestions. So my 05 Evo wont build boost past 10-14 lbs of boost. Sometimes it will sputter at 10lbs, and then other at 14lbs, and then wont build boost past the 10 or 14lbs. I ordered a boost leak tester and new plugs. I changed the plugs today and the problem is still there. Im gonna do a boost leak test, however I was wondering if anyone has any other ideas that could be causing this problem?

 

what boost controller you running

 

Make sure you vacuum lines are connected properly and not damaged.
Check your sparkplugs. Make sure they are gapped correctly and not fouled.

 

Spark plugs are good, and gapped properly. I just installed new ones since I thought that they were teh cause of my issue. Im running a grimspeed boost controller. This morning on the way to work it actaully hit 20lbs but was sputtering at 20lbs. First time its hit 20lbs since this started several weeks ago.

 

I thought that I would post my findings so that it may help someone else down the road. The issue ended up being my fuel pressure sensor that was bad. It connects to the vacuum side of the FPR. So basically I wasnt getting enough fuel pressure, hence the fuel cut sputtering sound. Thanks to everyone who replied.