P0174 Code At Idle

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by justadodgeman, Apr 22, 2014.

  1. I don't have freeze frame data to prove it but I can drive it around for a while after clearing the code then when I shut it off and turn it back on the code pops up after a minute. so that tells me its a vacuum leak and not a fuel delivery problem cause it only affects the car at idle(idles a little rough but barely noticeable) so the egr valve when I did the smoke test barely leaked but I would think that would cause a p0171 and p0174 code correct me if im wrong. ive checked everything but that's the only problem ive found
  2. stock 96 mustang gt btw
  3. I've had a slight exhaust leak that through a code at idle.
  4. ive checked but ill check again. is there any better way beside feeling and listening for exhaust leaks
  5. alright so after advanced auto denying that their scanners did live readings a until I showed them on their website that they do they finally helped me out haha the long term fuel trim for bank 1 was fine but for bank 2 it was at 25% and didn't get any better till about 3500 rpms so that's telling me its a vacuum or exhaust leak right?
  6. p0174 bank 2 lean . check for leaks in the pcv system , ck the valve , also things like intake gaskets can cause leaks , depending on the bank a plugged fuel filter can also cause a lean code on one bank , as can the evap system . egr valve would most likely effect both banks.
  7. If it was a fuel delivery problem Im pretty sure the ltft would have gotten worse at higher rpms so I think that rules out fuel filter but im gonna get a propane torch tomorrow and see if I can find leaks anywhere. I have just replace the pcv valve and ta is on bank 1 but how would I check it anyways? I know nothing about the evap system but where would that leak from? tell me if this makes sense please-if the egr valve is stuck open and the tube from it goes to the bank 2 manifold therefore it is sucking exhaust out and making the o2 sensor think there is an exhaust leak making it run lean?
  8. if the egr valve was staying open the engine would run slightly rough at idle and most likely lodge a p0401 or p0402 , the best way to look for leaks is with a scan tool capable of real time data and some carb spray ,while monitoring , the short and long term fuel trims spray the carb spray around the gaskets , hoses , valves and such , if the short term fuel trim drops that area is most likely the leak .
  10. ok the valve stays open a little bit cause only a little smoke leaked through but it not enough to throw a code I guess
    I don't have a scanner but I tried propane and carb cleaner and found no leaks, fuel filter is brand new and so is pcv valve but how would the pcv valve cause a lean code? im wondering cause id like to check it out and make sure I didn't get a defective one.