Hell

What’s the black thing circled? Also any info on what the hose is that’s circled as well ? I have a 2004 Monte Carlo SS supercharged and just recently has been jumping at idle, wants to stall at idle, will act like somebody’s driving it and RPMS will just increase, Rpms sometimes falls below 700 rpms as well, replaced idle control valve already.

 

car has been throwing a P0455 code for a while but never seemed to affect the car

 

The smaller part is called the vacuum manifold and the hose is the vacuum manifold to brake booster hose.

Check for vacuum leaks first. You can use an unlit propane torch. Just blow propane anywhere you think there could be a leak and listen for dramatic idle changes.

Could be the evap canister, could be MAF, could be BBS.. Could be a lot of things but check for leaks first.

 

Before buying more parts, I'd buy a basic OBD diagnostic tool that could read codes and live sensor data. It would help you understand what's going on here by looking at the inputs and outputs and would help you in future issues if you decide you want to continue to maintain your own cars.

 

Just a little FYI if that brake booster hose becomes loose or detached from the Brake booster they usually wont run or be real hard to start. .

 

So I have a basic OBDII sensor, used it before and never had any codes, ended up replacing the vaccum
manifold, and now it’s throwing a p0300 code but it was never there before, and car idles a little funny still, seems like it’s loss of power though as the interior lights dim out. Could it be a false code ?

 

Have you done a vacuum leak test yet? If you cant do the propane thing, get OBD info on it. Should be -20 at idle. Full throttle boost pressure could help also.

Do you have an IR temp gun? Can you get the exhaust temps from each runner on the exhaust manifolds? We could tell you if the po300 is false or not (most likely) if you could get the temps.