2001 troubles multi codes, gas guage messed up, stalling/lunging

My friends got a 2001 Impala 3400. its acting weird. some times the gas guage bounces from F to E and back, the throttle is sticking(you put it in gear and it lunges and goes with out touching the gas), It has stalled once and the engine seems louder than normal. it runs fine most of the time but it when it acts up it does all of the systoms at the same time. I scanned it today and came up with 5 codes...

108 MAP high voltage
122 TP sensor low voltage
452 fuel tank pressure sensor low volt
446 EVAP VENT system performance
1665 EVAP VENT solenoid circuit

stall/loud engine/gas guage acting up/throttle acting up...

any help or ideas would be great thanks..

A full scan will look at these inputs vacuum to map could be skewed, tps could be bad or miss adjusted, this can cause the stall erratic idle, the other codes are caused by the closed tank vent system leaking or malfunctioning, usually not connected with the performance issue. Gas tank float could be bad or bad connections at the tank. These issues will need more comprehensive diagnosis to track down, vacuum leaks under the hood could involve some of these codes.

My friends got a 2001 Impala 3400. its acting weird. some times the gas guage bounces from F to E and back, the throttle is sticking(you put it in gear and it lunges and goes with out touching the gas), It has stalled once and the engine seems louder than normal. it runs fine most of the time but it when it acts up it does all of the systoms at the same time. I scanned it today and came up with 5 codes...

108 MAP high voltage
122 TP sensor low voltage
452 fuel tank pressure sensor low volt
446 EVAP VENT system performance
1665 EVAP VENT solenoid circuit

stall/loud engine/gas guage acting up/throttle acting up...

any help or ideas would be great thanks..

step # one, clear the codes and drive the car, rescan the code and see what came back. some of those codes could have been there from awhile back, youll need fresh codes to work with

if it stalls and lunges it sounds like possibly a vacuum leak. have you done an intake on it latley? did u forget to hook up the main vacuum line that goes to the intake on the upper plenum on the passenger side?