P0171 AND P0174 Error codes

[statey1975]

Hi all.

Firstly, the vehicle details:
2003 LS1 WK Statesman, aftermarket vapour injected LPG system installed

Lately I have been having the check engine warning pop up, after running ProScan it's returning the P0171 and P0174 bank 1 and 2 lean warning. But, it's only happening on LPG.

I've had the gas system checked twice, and the tech advises that the system is set up perfectly, and it does drive beautifully.

It has been suggested to replace my O2 sensors, but I find it unusual that the problem only presents itself when running on LPG. I guess, though, that it is possible the O2 sensors might be a little more picky when running on LPG.

Any thoughts? Suggestions?

 

[PlenumBiscuit]

i had similar errors when i first got my VY v6

i simply cleaned out my throttle body and plenum thoroughly and the errors went away

i dont know the stato engine but may work for you, clean out the gunk around air intakes

 

[statey1975]

For those who may come across this problem in the future, on petty or gas, check your PCV hose. Turns out mine was perished and crumbled where the hoses join at the back at the motor, and also the valve broke inside the hose where it connects at the throttle body.

Rather than pay Holden over $120 for a new PCV hose assembly, I got a vaccuum Y-piece, a couple of bits of hose, and had the problem fixed in about half an hour for around 15 bucks.