Hi im new here but ive been reading all the posts for awhile here since i got my vehicle. (2000 pontiac grand prix 3.8 sc) First things first i was initially getting evap code so i changed my gas cap and had my light turned off. I also replaced my air fliter. shortly after my light came back on. But then it would turn off and then back on again. I did have it blink a few times one time then shut off. But a couple days later it came on and stayed on so i went to AZ and had it read again and it stated i had the same p0144 code i believe it is and then i had the new p0171. and after reading this forum i knew i was in for it. My initial thought was maf so i took it off and cleaned it up. I also cleaned my egr and pcv while i was at it. And the light is still on ive tried shutting the light off by disconnecting the neg bat cbl for like 10-15 mins but it hasnt shut off so im assuming it can only be shut off with a computer.
Ive recently installed a sound system and hooked up my positive to the easy access spot for the battery but i highly dought this is it bu i have read some stuff about battery connections cousing the code but i dissconnected them cleaned them up(they really wernt dirty) and put them back on nice and tight. I thought also a vacuum leak and i sprayed all along the hoses with carb cleaner but found no difference in idle. I do however hear a small leak sound but my boss( ase mechanic) says he thinks its a exaust leak. I havnt changed my plugs and wires out since ive had the car about 10k miles. I have read alot about this code and want to narrow it down im just kind of unsure were to start. I think i might have a smoke test done to make sure there is no leak. The car has 191k miles but the engine was rebuilt about 50k ago and runs great up till this. Im not having a huge power loss but it does seem like it doesnt have the power it had befor. Im going to change out the plugs wires and fuel filter and see if anything changes. (what do people recommend for these) and after that if no luck im think o2 sensor but befor i dump the money into that is there and easy way to check it. Any input would be greatly apreciated, i really dont have much money im working at a gas station/garage so ya... lol thanks in advance