2000 chevy runs rough changed fuel pump fuel filter o2 sensors o2 sensors still show bank 1 #1 lean bank 2 #1 lean will run 200 miles i will shut it off do what i have to do start it up and go 3 to 4 miles and it will stall it will start up after 5 min and go 20 miles somtimes 100 miles

• Dale, code P0171 fuel system too lean
• Possible causes
• change fuel filter first, if it has not been done recently

RESTRICTED FUEL SUPPLY LINE
FUEL PUMP INLET STRAINER PLUGGED
FUEL PUMP MODULE
O2 SENSOR
O2 SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
O2 SENSOR HEATER OPERATION
TPS VOLTAGE GREATER THAN 0.92 VOLTS WITH THROTTLE CLOSED
TP SENSOR SWEEP
MAP SENSOR OPERATION
ECT SENSOR OPERATION
ENGINE MECHANICAL PROBLEM
FUEL FILTER/PRESSURE REGULATOR (HIGH)
PCM
Check the attached links,
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."

2000 Jeep Grand Cherokee p0171

Possible problems related to Code P0171 Jeep Garage Jeep Forum

P0171 System to Lean Bank 1

Code P0171

Sounds like you have a vacuum leak. Although, it could be bad o2 sensors. If the computer sees that the o2 sensors are showing lean then it will increase fuel flow to try to even out, which causes it to burn more gas.

Have you checked/replaced the O2 sensor(s). They produce the data that your computer reads. Bad/clogged O2 sensors will trick the ECU into running lean/rich.

could still be a vacuum leak.

I’m happy to assist further over the phone at https://www.6ya.com/expert/josh_8f8ad0a8f7e0e6d3

how many miles on the odometer, mines 95k.
ah a v6, P0306 is #6 misfiring. 2.5L V6
300 is all 6 misfiring.... oops.
it is. for sure.
misfire is cause by many things, only 3 in physics, but many real world. (compression + spark +fuel rates)
i works this easy, way.
i have a full scan tool not just a code reader (near useless it)
i make sure my V6 (I have an 04) holds closed loop at idle and 2500 rpm. i f not , fix that first.
easy, it is. just look, bingo, Open loop, (out of control)
fueling is out of control.
but, first i do that tune up. in the manual, 60k , 120k, 180k, see?
do that first. , spark plugs dont last foreever nor filters.
then i replace both front 02 sensors at 100k miles. there design life.
V6 has 2 front sensors. (rear can , just sit and be ignored)
if it misfires. now, i toss a coin.
compression or fuel pressure.
i can do both in 30min flat but i toss coin lands on fuel.
i check fuel pressure and its.
60psi, fuel regulator is bad,
20psi, same, or bad pump or bad 12vdc to pump, 8v to pump is bad wiring.
one thing that helps is to find out if the engine is running too rich or too lean.
and if there are cracks in the exhuast near the 02 sensors.
i force the EFI rich and lean watching both 02 sensors in my scan tool
to see if i can force them lean or rich.
on the v6, we can introduce air leaks, to the plenum.
this will cause lean, and the o2 most react to my lean forcing
or its dead.
i can force richer, if i suspect lean or 02 shows lean, by
removing the Fuel pump regulator hose (vac) and plugging hose fast.
this causes the FPreg to go to high pressure. max.
causing RICH>
i watch the 02 and see it go rich, if not the 02 is bad or you have exhaust leaks, or dead cylinder causing the 02 to fib.
you have 2 banks, and both banks are running off 1 MAF
so you can look at both 02 sensors (front) B1S1 and B1S2
and see if both react the same. to my forcing's.

i dont think you have 3 bad cops out 6. no.
if any cylinder misfires on bank one, then bank 1 o2 goes nuts
same with the Bank 2. this can aid troubleshooting having 2 banks.
the MAF can not lie for 1 cyclinder nor one bank
the 02s can lie for each bank,
both are key to diagnosis.
let me give an example say
injector 1 leaks.
causing 301s
v6
246
135 left
this is your lay out.
my guess is its not lost compression (no test guess, mostly useless)
not 2 bad cops one on each side will cause 300s
not one bad cop. as other side would be ok.
not one bad injector.
my guess, is fuel pressure is way off.
but///???
or maf running lean (dirty, spary clean it 12inches away not close)
low fuel pressure
too high fuel pressure.

all comments are for engine with 60k mile service done,
60k, 12ok, etc.

probably both banks are running lean it just hasnt flagged a code for bank2 yet.
sounds like a vacuum leak, with it running listen closely in the engine compartment try to locate it.
also you can use choke cleaner and spray around the intake manifold
and try to locate the leak.
be careful choke cleaner is flamable.

P0302: Cylinder #2 misfire.
P0171: System too lean, (bank 1)
The first may be a bad spark plug or the wiring to it. If it has been some time since the engine has had a tuneup, change all spark plugs and plug wiring. Check the air cleaner and replace if dirty. If it runs much better, recheck the codes again. If the car has 100k miles or over, it wouldn't hurt to replace the O2 sensors as they do wear out (even though the codes don't show that at this time). Replace the fuel filter as well. Running some injector cleaner through in the fuel will help too. If still having problems, check the system fuel pressure as the pump may be on the verge of failing. Again, the codes don't show this as a problem yet. Good luck.

If this car uses an electrically heated O2 sensor, the heater portion may be bad. If the car has a lot of miles, the O2 sensor may be getting bad also.

there is only one bank on a pt cruiser and yes it could be a fuel pump or a vacuum leak

P0171 - Fuel Trim System Lean Bank 1
YOU WILL NEED TO AVE THE DEALER TEST THE O2 SENSOR FOR PROPER SWITCHING, RIGHT NOW IT SHOWS ALWAYS LEAN, THIS MAY BE THE SENSOR OR THE ENGINE MAY REALLY BE LEAN ON FUEL AIR RATIO, AS FAR AS THE SMOKE GOES THE 2 ARE PROBABLY NOT RELATED, HOW MANY MILES ON CAR? IF THE MILES ARE HIGH THEN REPLACE THE O2 SENSOR ON THE CYLINDER BANK WHERE # 1 CYLINDER IS LOCATED, THE SENSOR IS THE ONE BEFORE THE CATALYTIC CONVERTER.