2000 Saturn L200 Starts then Dies - Saturn LS2 V6 3.0

Cold engine will crank & start, rev to about 2000rpm then die. Repeat process 6-8 times, engine will stay running at about 2000rpm w/lots of misfiring then level out after warm up, however, when driven has no power, 25% pedal only, push pedal past that and engine chokes. Pulled DTC's: P0300/P0171/P0174/P0154.

Fuel rail pressure at startup through warmup steady at 48psi even during rev up, engine off, 2 min later still 48psi. I found intake leaks in pleats of intake hose downstream from MAF, repaired it, also found major coking in pcv port to throttle body hose, cleaned it, cleared DTC's and re-scanned and to my confusion pulled code P1511.? Why wasn't it there before?

Now, cold engine will crank & start, rev to about 2000rpm and die, repeat 6-8 times and engine tries to stay running (about 400rpm while misfiring) then will die. Cant get engine to stay running to get warmed up now. I'm assuming the intake leak gave the engine enough rpm's to stay running through the misfires. Also, another thing I noticed, when trying to start it now. If you start it from the key "off" position, engine starts and revs to about 2000rpm then dies but if you start it with the key from the "run" position, engine starts and revs to about 1000rpm then dies, not sure if that helps. Would also like to mention this vehicle doesn't have an accelerator cable and when engine is trying to run (400rpm while misfiring) if you push on the pedal nothing happens, almost feels as if its not hooked up, yet when the engine is warm you have 25% pedal.

Whats with that DTC: P1511? Why wasn't it there the first time I scanned?
Could this be a throttle body problem or did I force that code when playing with the throttle linkage when the engine was running?
Or could this just be a TPS/TAC, IAC or my strong guess, coolant temp sensor?
Problem is not knowing +/- values/ranges of all the sensors, not sure what to test for.

Please help! Pulling my hair out on this one!

Thanks again!