I have a 1997 GMC Sierra 1500, 5.7L 350, 4X4. The fuel pump went out while driving. It also threw the check engine light. I hooked up a fuel gauge and it showed the fuel pressure to be about 50psi and then bleed off when the fuel pump shut off (engine not running - key in on position). Due to the bleed off I though it was the fuel pressure regulator. Replaced that but the truck would still not start. Also there was no excessive fuel in the plenum when I pulled it off. I replaced the fuel pump and the truck started and ran. The check engine light was still on and showed the codes P0171, P0172, and P0174. This is what I have replaced so far in this order after the new fuel pump and FPR (the code was cleared, returned, and checked after each part) - fuel filter, air filter, cleaned mass airflow sensor, replaced mass airflow sensor, new spark plugs, new SP wires, and BG44K fuel treatment. THE CODE IS STILL COMING BACK!!! Please help!!!
YO HAVE A VACUM LEAK AT INTAKE MANIFOLD GASKET OR HOSES THATS YOUR PROBLEM USE A CAN OF CARB CLEANER TO HELP FIND LEAK BY SPAING ARROUND INTAKE OK HOPE THIS HELPS BUT IM SHORE THATS YOUR PROBLEM RESON YOU REPLACE YOUR FUEL PRESSURE REGULATOR LEFT INTAKE LOSE OR PINCHED GASKETS OR LOSE HOSES TRY THAT OK
I have tried spraying some carb cleaner but I will try again and be more thorough. Thanks for the response.
ONE MORE QUESTIONS DID YOU REPLECE YOUR FUEL FILTER IF NOT REPLECE IT OTHER I KOW YOU JUST REPLECE FUEL PUMP BUT SOME TIMES THERE BAD CHECK YOUR FUEL PRESSURE IT HAS TO BE AT NO LES THEN 58LB RUNING AT STARTUP HAS TO BE 65LB OTHER WHEN DOING THE PRESSURE TEST TURNKEY ON ONLY LOOK AT GAGE LOOK FOR LOSS OF PRESSURE FOR AT LEAST 5 MINUTES OK LET ME KNOW
I did replace the fuel filter. I hooked up fuel gauge again and no loss of pressure so all is good there. I checked the vacuum again and could not find any leaks. still stumped
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SOURCE: 1996 s10 2.2 engine starts but idles rough and will not rev up.
Hi! You must be frustrated by now! your code is marking that the O2 sensor is bad in bank 1. Did you replace the O2 sensor that is located before the catalytic converter? The S10 has an O2 sensor specially made for that cat. its about 30$ That would explain for your blackened spark plugs; your pc on the car is asking for more fuel. GOOD LUCK!!
SOURCE: check engine light on,running rough and stalling.
means you have multiple misfires (po300) the other codes are lean codes, possiable tune up , bad injector, fuel pump,
SOURCE: check engine light on,running rough code P0172
When I see all these codes i instantly think of two things. Vacuum leak especially intake manifold gaskets and Mass air flow sensors. Spray the engine with carb cleaner when its running and see if you get it to rev up,run rough or run different. Next unplug the MAF and drive the car, see if it runs normal.
SOURCE: Check Engine light is on my 1997 F150 with a small
CODE PO171 SYSTEM ADAPTIVE FUEL TOO LEAN BANK 1. CODE PO172 SYSTEM ADAPTIVE FUEL TOO RICH BANK 1. CODE PO174 SYSTEM ADAPTIVE FUEL TOO LEAN BANK 2. CODE PO175 SYSTEM ADAPTIVE FUEL TOO RICH BANK 2. ALL CODES COULD BE CAUSED BY AIR LEAKS AFTER THE MASS AIR FLOW SENSOR OR LEAKS IN THE PVC SYSTEM.EXHAUST LEAKS BEFORE OR NEAR WHERE THE HO2S IS MOUNTED.FUEL INJECTORS RESTRICTED OR NOT GETTING ENOUGH FUEL WEAK FUEL PUMP. LEAKING EGR GASKET OR LEAKING EGR VALVE DIAPHRAM.MASS AIR FLOW SENSOR DIRTY CAUSES PCM TO UNDERESTIMATE AIRFLOW.
Testimonial: "Thanks for the . I changed the PVC valve and fuel filter and was able to reset the codes (I couldn't before). So far so good."
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I did replace the fuel filter. I did the vacuum test again and did not find any leaks. Still stumped.
ok for codes that your giveing p0171 p072 p0174 thats telling me bank1 and bank2 are runing lean ok vacum leaks got that fuel pump got that please recheck fuel pressure should be no less than 56lb ok fuel filter got that check little arrow pointing tours front of truck ok mass air flow sensor make shore all clamps are tied next it be your 02 sensors it take four of them sense both banks are lean it be ethere all four or two of them kind of weard if all four whent out at same time hmmm othere you mention that you added a treament to your gas tank thats not good see by adding a treatment on gas tank it cleans your gas tank and all trash on tank goes to your filter and injectors you mite have dirty injectors only a shop can clean your injectors or put a scaner on it to see how 02 sensor are operateing love to have your truck heer so i could help more let me know
Thanks for all the help! Arrow is good on fuel pump. Fuel pressure is about 62psi. I think I am gonna have a shop put the scanner on the truck to see how the o2 sensors are acting.
thats best you can do just ask them and is they say your 02 sensors are bad pay for diagnose and you change them there not that expessive at a pepboys dont use auto zone parts ok let me know if i can help more
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