Codster roadster

i have a po171 and po153 code. the scanner im using says the po171 code lit up the check engine light its a bone stock 98 gt.

po171:

RPM:2850
LOAD VALUE:89.4%
COOLANT TEMP:185'F
56 MPH

short term fuel-trim 1: 10.1%
long term fuel-trim 1: 25%
short term fuel-trim 2: 11.7%
long term fuel-trim 2: 25%
short term fuel-trim 3: 60.9%
long term fuel-trim 3: -44.0%
long term fuel-trim 4: -39.5%
short term fuel-trim 4: 97.6%

If anyone can point me in the right direction to fix this problem i would be extremly grateful

...also my car doesnt have any trouble idleing, accelerating or starting up? thank you.

Repzard

P0171 is a lean code bank 1 I believe off the top of my head.
Make sure you do not have any air leaks after MAF.(Intake area before TB)
Also could be caused by a dirty MAF as another option.Can try cleaning it and reseting codes.

P0153 is Oxygen sensor related..Could be failing?Maybe setting both codes?
My guess is its in bank 1 side of engine causing issue

Codster roadster

ive replace the o2 sensors that are after the cat. weird thing is the ones that were on there originally werent the same? one was skinny and had ford on it the other was fat and had no brand on it? i got the new ones at rockauto "ultrapower" was the brand. it said OE style. so i guess im goona replace the ones after the cat next? also when i ran a monitor test all my systems worked fine excpet it said "evap system inc"?

Codster roadster

Also I was looking under the gas tank and noticed two nylon fuel lines were loose. It looks like they are going to the two tubes on the fuel pump?

cliffyk

P0171 is lean on bank 1 (a front sensor issue) . P0153 is slow response on bank 2 sensor 1 (HO2S-21, Heated O2 Sensor, bank 2, sensor 1), driver;s side front sensor.

I am confused by you statements, your said "ive replace the o2 sensors that are after the cat." and then "so i guess im goona replace the ones after the cat next?" So what is it that you have already replaced?

As the codes indicate both banks I would concentrate on things that affect each bank separately. Exhaust leaks before or near the front O2 sensors could cause both codes--lean on bank 1 and slow response on bank 2...

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BTW, DTCs are always one letter and four numbers--P0171, not Po171...

Codster roadster

Sorry lol I mean I replaced the ones after the cat. So i guess I'll change the ones before the cat next? Also I put the car up and I can't see any exhaust leaks. Would there be a noise if it was leaking from the header gasket?

cliffyk

Before changing the sensors make sure there are no exhaust leaks. You can bench test the sensors with a multimeter and propane torch...

Codster roadster

Thanks alot I appreciate all the help. But I'm fairly sure there's no exhaust leaks? And let's just say the sensors are ok. What else could be the culprit? I've sprayed the intake and intake manifold and most of the engine with starting fluid and the car idled perfect. So that might rule out vacuum leaks?

cliffyk

Other causes are all listed in the links I provided in my 1st post, post #5, above--work the lists from top to bottom...

Codster roadster

Thanks so much man