egr valve
Post Fiend
Joined: Jan 2003
Posts: 9,748
Likes: 16
From: Connecticut
P0172 = System Rich, Bank 1 (Passenger's side of engine)
P0174 = System Lean, Bank 2 (Driver's side)
Seeing those codes together is somewhat of an anomaly, at least to me. It means that one side of your engine (Bank 1) isn't getting enough air and/or is getting too much fuel. Yet the exact opposite is happening on the other side of your engine.
One guess I can offer is that maybe your MAF is malfunctioning, sending a signal that's all over the place to the PCM, resulting in the PCM telling the fuel injectors to fire at inappropriate times. Another thought is maybe your fuel pressure regulator is out of whack.
Are you experiencing any driveability problems? Hesitation, hard starts, bad gas mileage, etc?
P0174 = System Lean, Bank 2 (Driver's side)
Seeing those codes together is somewhat of an anomaly, at least to me. It means that one side of your engine (Bank 1) isn't getting enough air and/or is getting too much fuel. Yet the exact opposite is happening on the other side of your engine.
One guess I can offer is that maybe your MAF is malfunctioning, sending a signal that's all over the place to the PCM, resulting in the PCM telling the fuel injectors to fire at inappropriate times. Another thought is maybe your fuel pressure regulator is out of whack.
Are you experiencing any driveability problems? Hesitation, hard starts, bad gas mileage, etc?
Post Fiend
Joined: Jan 2003
Posts: 9,748
Likes: 16
From: Connecticut
Originally Posted by mrmcdb2005
hard starts and hesitation and it was p0171 anf p0174 both to lean. i done checked for vaccum leaks do not have any. the truck has 97,000 on it and ore the origanal o2 sensors should i change them.
Could still be related to fuel delivery and/or fuel pressure. When's the last time you changed thefuel filter? How about fuel injector cleaner, do you ever use it?
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yes i have used a lot of injestor cleaner but the motor in the truck is not the orginal motor i heard sometimes the ijectors after setting a while will gel up and can not be cleaned is that true. it also hesitates at low and high rpm
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I previously posted regarding my 99 3.0 hesitating and idling rough only while the ac runs. If I turn the ac off it runs fine. The ac blows ice cold so charging doesn't appear necessary. I have replaced spark plugs, air filter, cleaned MAF and throttle body, replaced IAC with no results. Guys have suggested plug wires or vacuum leaks, but that wouldn't appear to be the case since it only happens with the ac on? Am I correct in my thinking?
I'm close to taking it to the stealership and dish out some cash. Any final thoughts from the techies out there? JJ
I'm close to taking it to the stealership and dish out some cash. Any final thoughts from the techies out there? JJ
Post Fiend
Joined: Jan 2003
Posts: 9,748
Likes: 16
From: Connecticut
The PCM is supposed to kick up the idle a little bit when the A/C is engaged in order to accomodate the additional load. This increase is noticeable, particularly when you are looking for it. Maybe something is breaking down between the PCM and the Idle Air Control (IAC) valve. Does your idle increase like this? How is your idle otherwise?
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JCastellaw
1987 - 1996 F150 & Larger F-Series Trucks
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Jan 16, 2004 11:35 AM
