RX300 codes P0171, P0330, P0250

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So my wife's 99 RX300 lit the check engine light and went into limp mode. Had the codes read and showed 2, one for air fuel ration and another for knock sensor voltage. I replaced the AF sensors front and rear first just because they are easy. no change. Next I replaced both of the knock sensors. this cured the knock sensor code but left me with a Lean Misfire on Bank 1. I cleaned the MAF, same thing so I replaced it, still the same. The last round I decided to replace the fuel injectors. While I had the intake off again I replaced the plugs and swapped the coils from the front bank to the rear, (if I did have a coil issue the code would should banks). It did run OK if you drive it like a Grandma. If you get on it, it will miss an sputter in the upper RPM range and throw the check engine light. P0171, P0330, P0250 are the current codes. Knock sensors are new along with other parts. right now I'm leaning to fuel delivery problems, fuel pump or pressure regulator.

I drive a truck OTR so I'm not home but a limited amount of time and have a limited amount of internet access  Because of that I've been dealing with this for over 6 months. Luckily I have a 92 Ford Explorer with 250,000 miles the purrs like a kitten she can drive 

Any insight would be appreciated

Vehicle is a 1999 RX300 AWD 140,000 miles. had a new timing belt and water pump @ 120,000, O2 post cat and exhaust repair @ 125,000 along with parts mentioned in the post.


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