Ka-t issues; ran perfect, now extremely lean

[skvngr]

Allrite, well my car has been down for 3 weeks now.. Still cant figure it out. It's ka-t, enthalpy tuned. Car ran perfect as can be, then one day my wideband started reading a little leaner than normal while cruising on the highway home. It gradually got worse on that same drive til it felt like crap and really hesitant. Figured it could be my fuel pump so i changed it and nothing. Also changed fuel filter, fuel pump sock, added inline fuel pressure gauge (my fuel pressure is good at 40psi), new o2 sensor.
Car still starts and idles but I cant drive it more than a block before it gets to the point where its undriveably lean. I dont know what could be the cause of my issue as its definately not something obvious. I need all the input I can get. I'm leaning towards it possible being my ecu (short or something) so I'm probably going to send it back to get it checked out and eliminating that as a possibility.

If it makes a differences:
stock ka
isis turbo kit
enthalpy tuned
550cc inj
z32 maf

[Darren]

i used to have a car that did something similar... there was a tonne of rust in the tank from it sitting for a long time, and it would constantly pile up around the pump sock. Once i let it sit for 5-10 min it would be fine for a bit.

Could be something like this, maybe something in the lines blocking flow...

[Edwin562]

could be your injectors, are they new??

[skvngr]

hmmm, its funny because after I changed everything I mentioned, it didnt really even want to stay idling. Then I let it sit for 4 days. Had my friend over and started the car to show him the problem, and the car stayed idling and never died out. But I went to go drive it, and it got leaner the longer I drove it down the block. Almost couldnt drive it back home because of how lean it was (it gradually got worse during that really short drive).

Injectors arent new, but they were working. I pulled the rail and checked them during priming, and they all sprayed

[waxball88]

If you aren't running a walbro the fuel pump is probably dying.

[skvngr]

its a walbro 255lph

[Tantwoforty]

I would check timing and spark plugs/wires
What plugs are you using? maybe there super nasty and fouled? i just had a issue with bad plugs..
Have you checked for a boost/bov/vaccume leak?
any check engine light?