well hello, i'm in need of some help, i have a 2002 silverado extended cav with the 4.8 engine in it, my proble started when i parked my truck after work like alway few minutes later i needed to go to the store to buy some groceries but my truck started to hesitate like it was gonna die, finally i manage to get it to idle, it drove weird i couldn't give it gas without it hesitatin, so i took it to autozone after my service light came on, the told me that my bank1 sensor 1 and bank2 sensor 1 were bad so i replaced them and also replaced spark plugs(the iridium kind) and wires, after i did that the hesitation was gone, but then my service light came back on,so i got another reading and it gave me a p0171 and p0174 code meaning bank 1 and 2 too lean but still the truck was runing without hesitation, so then i decided to replaced the air filter and put some injector cleaner in the tank,i started the truck and it stareted to hesitate again even worst, now i can barely star it, it will start and then the idle will drop and die.
i'm not raelly sure waht to do next, maybe replace my MAF sensor since it is beside the airfilter and it might be bad, i want to check for vacuum leaks but don't really know the best way to do it. if anyone can help it will be greatly apresiated. thanks everyone!!

 

If its running lean then there is a vacum leak somewhere. The quickest way to pinpoint it is spray some starter fluid around the intake all over little by little to see if the idle goes up. If it does then that should tell you where its leaking from.

 

update: i came home from work and now i can't even start my truck, can it be the fuel pump? i have no clue and can't even take it to the shope to get it check.

 

When you turn the key on but not start the motor can you hear the pump whine for a couple seconds in the tank??

 

i couldn't heard anything cuz i had the door open, i'll give it a try.

 

nop i didn't heard any sound coming from the tank .

 

hit the tank with a rubber hammer if it start the fuel pump is going bad

 

ok i'll give it a try.but would the pump make the engine to run lean?

 

It could the problem or it could be small intake leak use propane to find it

 

i'll try to get some, but how i'm i gonna check for leaks if the engine won't start, it has to be runing for it to suck the gas doesn't it?