Hanging rpms and lean codes...
So I've got a 2003 3.8 v6 5speed, just did plugs, wires, coil pack, IAC, cleaned the MAF, throttle body, and changed the fuel filter. Ran great for about 50miles, then the rpms started to hang when shifting and when coming to a stop. Doesn't matter where I shift from, 1500 rpms 2000 rpms etc. I found that I can do a IAC mod and make the wholesale smaller so I'm going to do that, for nown the iac is just unplugged to get rid of that issue. The other issue I'm having problems with is it also produced codes p0171 and p0174 (bank 1 and 2 too lean) along with these issues. I've read all over forms, most say check your vacuum for leaks. I've done that, and the only thing I removed during the install of the parts was the air intake which is a basic k&n. It's all tight. What could possibly make the sudden CEL after the tune up? I don't have issues idling, just hanging rpms.
Mods - CAI, 93 sct tuner, v8 exhaust port.
The plugs I just put in are Plat ngk, 8.5mm mds wires, mds coil pack