Trouble codes

[rngrmat]

It's been a while since I posted here but I'm always checking up on everybody's projects. A quick refresher of what I have. 94 Ranger reg. cab short bed with 95 mustang donor. T5 manual, 347 shortblock with steel crank and H beam rods from CHP (Coast High Performance). E303 cam with motorsport 1:6 roller rockers, Edelbrock heads with 202 intake valves, Edelbrock performer intake, 24lb injectors, 70mm throttle body, spacer and mass air meter, 190lph fuel pump, Cobra computer, underdrive pulleys, mac shorty headers, 2 1/2" dual exhaust that tie into a dual in dual out Flowmaster muffler. It was not long ago that I finally got the smog certification from the California BAR. They gave me a hard time about the dual bed cats, the adjustable fuel pressure regulator, and not having the stickers with E.O. numbers stuck on the truck. Once I corrected all their issues, I brought it back and it passed with ease.

It only has about 2000mi since the certification and I recently saw the check engine light come on and intermittently comes on while on the freeway. Running the codes....KOEO 111 (system pass) 181 & 189 (right and left still lean at richest adaptive limit during part throttle) The first thing that comes to mind is possibly a vacuum leak. Am I on the right track? I checked the fuel pressure and at idle it is 34psi and without vacuum it is 39/40psi. I have a stock regulator in there with the factory fuel rail. The KOER test only showed code 111 (system pass). Any light that could be shed would be appreciated.