Not building boost

**gonnakill25** · 08-22-2016

So, to start from the beginning My car was running a bit rough in the heat and I couldn't figure out what was causing it.(Ran almost perfect in cold weather, which I live in washington so its cold most of the time.) And I replaced all my struts, brakes, and so I needed to go in get an alignment so I took it to midas and I figured while it was there i'd just pay the 98 bucks to get them to run there bull**** test to see if they could find any codes (it does not and never has had a CEL) which it pulled a code for fuel pressure regulator which whatever replaced it wasnt that, and they said they found a vacuum leak on my supercharger with a bad O-ring somewhere. So I thought cool beans well its something. Well ever since I got it back from them I can't build boost correctly and whenever it tries it starts jolting. I don't know what they could have done. no matter what I do I don't get more than 1 psi of boost and has no power feels like i'm driving a n/a car. any help would be appreciated.

'02 Pontiac Grand Prix GTP, 188k, no mods atm most i've done to it is take care of it and have a k&n box filter.

**Scottydoggs** · 08-22-2016

have you done a tune up at all?

could be a clogged up cat if it feels really powerless.

other then that some pics of the engine and the vac lines might help. or a vid of it in action.

**gonnakill25** · 08-22-2016

it needs a tune up but I don't see how thats related to boost... and is there any test I can do to see if the cat is clogged? I don't see how it would just all of a sudden happen after I get it back from them.

**gonnakill25** · 08-22-2016

not really a way to vid it in action since it does it while driving. But I'll take some pics of the engine tomorrow after work.

**Scottydoggs** · 08-22-2016

if it needs a tune up i will misfire and run poorly and not turn rpms like normal, and fail to make boost.

if the cats clogged it will kinda sound like a vacuum cleaner with a full bag when you floor, and have no power. the cel can flash when its floored as well.

it could also be a bad bbv or a vac line. spray the bbv the map sensor and the all the vac lines with carb cleaner, if the idle jumps up you found your leak. you can also spray the sc to lim injectors and tb gasket area and the egr tube looking for a leak.