I've developed a boost pattern of 12/14, 8, and then down to 6 at about 4700 rpm. The car also shows only 15hgs of vacuum at idle, about 14 after I've run it some. I've gone through all the vac hoses, replaced some that looked bad, tightened all the hose clamps, checked my Y-pipe connector and the pill lines, and everything looks fine. The fuel filter was changed less than 5k ago, as were the plugs. I have no mods, other than a K&N air filter, on the car. Could it be the pre-cat. There just is no punch after 4000 rpms. I'd appreciate any advise.

 

how many miles are on your engine? If there are alot, your Pre-cat (most likely out of the two) or Main cat could be clogged, but I doubt it would make it fall that low so quickly. If u have alot of miles, id just change ALL the vacuum lines to get it out of the way, not just the ones that look bad, cuz u cant see cracks in them unless u take them off and bend them and such. Even then they will prolly just shatter.

Id say get a downpipe, but watch the boost if your hitting 12 psi already, and change all the vacuum lines. Your going to have to do it one day, might as well do it now that u have a problem.

 

It has just under 51k miles. Most of the vacuum lines look brand new.

 

It seems like it has the symptoms of restrictor pill loss, but the lines are on and tight.

 

bump

 

what was the pattern before? are these stock turbos? was the vac reading higher than 15 inHg before when you had good pattern?

you may want to play with a manual boost controller

 

The pattern was normal before, 10/11, 8, 10 down to about 8 at redline. Everything on the car is stock. And the vac read around 15 - 16, unlike now when it's 14 - 15.

 

Have you always had this boost pattern or did it develop recently? You are at 4600ft, right? You may be seeing some effects of altitude. Maybe.

edit: sorry, didn't read your last post. If you had a normal boost pattern at that same altitude, then that's obviously not the problem. I'll go away now...

 

I have the same boost pattern right now with DP, MP, catback, and intake. I replaced several check valves and that only temporarily fixed the problem. I still haven't found a solution for it.

 

Do you remember which check valves you replaced? How temporary was the fix????

 

Guess I'm going to be changing out the solenoids and controllers. Any online place that sells these, or do I have to go to the dealer??