Misery13

Been working on a misfire issue (P0300) with my 2008 grand prix gxp for a little while now, and discovered I also have a throttle body sensor issue. Hoping that replacing it will also fix the misfire (I know I know Im just avoiding taking the valve covers off and the heartbreak of seeing a collapsed lifter). While I was removing the old vacuum line from the throttle body it shattered into pieces. I see where it connects above the fuel rails, but I cant seem to find what this is. I think its something to do with fuel or oil pressure? PCV valve? I think I will end up just using the fittings from the old one and making a new one but I figured Id check to see if anyone had any experience with it, also genuinely want to learn what that vacuum line does.

The reason I think this might solve the misfire is, the car also had a short to the engine coolant temp sensor and the lifter tick noise got softer when I fixed the short. Hoping that the throttle body position sensor is causing the ignition system to not function properly. After saying all this out loud I am realizing this is a long shot and I will most likely be removing my valve covers today lol. If its a lifter that might be above my you tube mechanic ability. Although my next step would be to go through the coils again to see if I missed something the first time.

Anyone know what the vacuum line that connects directly to the throttle body is called/connect to? What type of hose do I make a new one with? Any vacuum hose?

rottonj

iTrader: (4)

Late to this, don't know if you found a solution. LS4 throttle body has a dead port, nothing goes there. Not sure if that's what you are referring to