I have a few questions and I'm not a master mechanic so bear with me.
So for the past few weeks my LS400 has lost a decent amount of power, idling a little rough and eating insane amounts of gas. I assume it's in limp mode? It's throwing 2 codes: P0100 P0110

One of those is a MAF sensor issue and one is the IAT sensor and I'm fairly certain that only the IAT sensor is out because it will put the car into limp mode and make it run rough and rich. From what I gathered it also messes up the MAF readings which is why it's throwing an MAF code maybe?

But as far as I'm aware, I have to replace this entire piece anyway because it contains both me IAT and the MAF sensors, right? I did mess around with it (I'm not sure what this part is called lol) and started the car with it unplugged, it ran a little rougher than it does plugged in and the engine cut off when it was unplugged while it was running.

I suppose I could just take it to a shop, but I'd rather do it myself because it seems simple enough lol.

 

you should start by cleaning the MAF with MAF cleaner.

After that I'd replace it. That would definitely put the car in limp mode

 

I just cleaned it today before work, it seems to have more power than it did before but the engine light is still on. There's a good chance it's just the code for the cracked EGR tube though so I'll have the codes scanned on my break tonight. Hopefully I fixed it!