silver86

iTrader: (10)

Can a missing oil filler cap cause a vacuum leak? I just got my car back together and I couldnt locate the oil cap but wanted to start it to check for leaks ect.. I noticed that the fuel trims were maxed out and I couldnt find a leak anywhere (ls6 intake). I was just wondering if the missing cap can cause the ltft to be maxed out? I know I should just go get one and try but I am busy the rest of the day so I figured I would post here lol

Thanks

99z28383

iTrader: (1)

Yes, your pcv system is hooked to the intake manifold. If it's not a sealed system, unregistered air is coming in and throwing your fuel trims way off.

grocerygetter

iTrader: (2)

And if in doubt, with the car idling put your hand over the opening, if u can feel suction it is throwing off fuel trims.