i have a 98 buick lesabre with a p0171 . i've cleaned the MAF sensor found Vacuum leaks and replaced the lines replaced the fuel filter and pcv valve, im planning on replacing the egr tube since thats a typical problem . i noticed that my light goes on and off . it goes off mainly when i put gas in the car. Can this have anything to do withe gas that makes the code go off? Any help would be great thanks

One vacuum leak that'* hard to find is in the gas tank or in the EVAP system.

Yea, the light going on and off only after fill ups must mean a fuel prob...what are symptoms of bad fuel pressure?

getting a lean indication is one. theres a black rubber boot with two hard plastic lines coming out on the throttle body check that for cracks, one of the lines goes to the lines goes to the fpr. check for gas smell real bad or leaks gas its bad. the other goes to the purge sel. check that for air leaks. i would think anything after that would give you a evap code

Start by checking the tube and your battery cables. I'd check fuel pressure etc as well. Maybe your pressure is getting low from a weak pump or dirty filter.

Yeah i actually replaced those lines i thought i hit the jackpot with that one when i got it

Yeah i will check the tube looks a bit difficult any tips on getting it out looks like its by the throttle cable. And what should i look for when check battery cables . When i changed my battery i noticed my positive cable the screw inside of it doesnt come out as far as the negative could this be the problem?