Ok so I’ve got a 2004 F150 lariat 5.4 with 223k on it with the dreaded P0174 and P0171 trouble codes. Here is a snap shot of the data I took from my OBDII reader. The pic shows the info when I was at around 2500 rpm. At idle the short term values are much higher. Also if you see the long term bank 2 numbers never change regardless of rpm. What is that telling me?

So from what I’ve read this points to a vacuum leak right? I’ve got a fog machine I’m going to use to smoke the engine and see if anything shows up but I’ve smoked it about a month ago with negative results but I was using a cigarette that time. Where is the best place to hook up to do a smoke test. Last time I used the brake booster line should I use a different hose?

Any questions or comments to point me down the right path would be much appreciated.