I used to have 16-18 vacuum at 800 rpms.

now since i got my car back from the shop, i had lumpy idle (400-600 rpms)

i fixed it by bumping the idle up to 900

At 90o rpms vacuum is 16

when the car is cold the rpms settle at 1500 and the vacuum is 16-18 closer to 16

i can't get to 18 anymore. Possible vacuum or is my motor lossing compression.

I boost 9 -13-13.

Mods are

blitz intake

down pipe,midpipe,greddy catback

HKS PFC FCON

manual boost controller



I think i'm running rich, the whole car is running rougher now at idle (shaking abit)

i have break up (stutters)in high rpms for first 10 min after warming up then goes away, oh there a back fire in there with the stuttering.

after it's warmed up it settles at 900- 700 rpms and vacuum is around 14-16. closer to 14. https://www.nopistons.com/forums/pub..._DIR#>/sad.png

what work was done at the "shop"?

Had the fuel pulsation damper replaced.

That's all

oh they hooked up my air pump, and disconnected it and my idle was alittle better, but i still had to bump up the idle screw about 5 turns or so.

Damn, there is alot of stuff you need to take off to rplace the FPD. There are numerous things they could have broken, left unplugged. It will be hard to tell if all the hoses and connectors are on coprrectly without taking off the upper intake manifold

Check all your vac lines and especially the boost sensor. they had to take some of the vac lines off to replace the FPD there is something like 7 vac lines that go to the UIM and two elec. connectors. check all those because they had to take UIM off to work on your car. How new is your O2 sensor? If you FPD is replaced then your 02 sensor could be reading differently from the proper amount of fuel being injected now. Sorry of this is too much but those are my Ideas.

I've never replaced O2 sensor. How long do the normally last