emissions experts??
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Joined: Jun 2002
Posts: 72
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From: Florida
Thanks for the help! You guys ROCK!!!
I have had a minor rough idle in stop and go traffic. I got the service engine soon light and had it scanned today. The code was reading lean on bank 2. I was told upstream O2 sensors MIGHT be bad. No clear indication though. Anyways they wanted like 450.00 to replace the 2 sensors and do some hoky upper engine cleaning. I just paid for the diagnostic and left. I got a second opinion and was told O2 sensors are a bit premature at 44000 miles and it sounded like possibly a minor vacuum leak or a dirty injector. I had the code cleared at the first place and bought some injector cleaner at the second place. I guess im just going to be content until the light comes on again ... if it comes on again. Any opinions out there on this issue.
2000 F150XL SC 4x4 4.6L 3:31
2000 F150XL SC 4x4 4.6L 3:31
Last edited by David Johnson; May 23, 2003 at 08:55 AM.
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Joined: Aug 2000
Posts: 379
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From: San Jose, California, U.S.A.
Sounds like a vac leak. or possibly a dirty MAF. Easy to check and easy to fix.
try reading here for some good info.
https://www.f150online.com/forums/sh...hreadid=104907
HTH
Jes
try reading here for some good info.
https://www.f150online.com/forums/sh...hreadid=104907
HTH
Jes
Technical Article Contributor
Joined: Jun 2002
Posts: 10,511
Likes: 10
From: Under the flightpath of old ORD 22R
David,
Assuming that they gave you the correct discription, it should be a P0174 DTC. I hope that is what it was, sometimes places can jack up a DTC problem description without even trying hard, and give the wrong text for a specific number.
You can do a search on p017* to get 38 posts on the topic.
Biggest ones seem to be dirty MAFS or the PCV elbow on the back of the T/B has a crack or leak in it. Those 2 are the major ones, but there are other things that is can be, down to a oil dip stick not completly seated ( not kidding, that is in the list of things ).
Other things have you checked you air filter as of late, or installed a FIPK. The reason I ask is if you knocked one of the lines loose from the intake, it is letting un mettered air into the system, and the truck is having problems compensating for it.
Try cleaning the MAFS ( do you also have pinging under load ?? ) and checking for cracks in the PCV lines behind the T/B ( yes it is a PITA, but it needs to be checked very closely ), before you go off checking other things on the list.
Let us know on the MAFS and PCV lines, as well as the other lines on the intake and the IAT also ( almost forgot that one ).
Here is the list from Ford.
DTC
P0174 - System to Lean (Bank 2) - see DTC P0171
DTC
P0171 - System to Lean (Bank 1)
Description
The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.
Possible Causes
Fuel system
Excessive fuel pressure.
Leaking /contaminated fuel injectors.
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel
Vapor recovery system.
Induction system:
- Air leaks after the MAF.
- Vacuum Leaks.
- PCV system.
- Improperly seated engine oil dipstick
EGR system:
- Leaking gasket.
- Stuck EGR valve.
Leaking diaphragm or EVR
Base Engine:
- Oil overfill.
- Cam timing.
- Cylinder compression.
- Exhaust leaks before or near the HO2Ss.
Diagnostic Aides
A SHRTFT-1,2 PID value between -25% to +35% and a LONGFT-1,2 PID value between -35% to +35% is acceptable. Reading beyond these values indicate a failure.
Assuming that they gave you the correct discription, it should be a P0174 DTC. I hope that is what it was, sometimes places can jack up a DTC problem description without even trying hard, and give the wrong text for a specific number.
You can do a search on p017* to get 38 posts on the topic.
Biggest ones seem to be dirty MAFS or the PCV elbow on the back of the T/B has a crack or leak in it. Those 2 are the major ones, but there are other things that is can be, down to a oil dip stick not completly seated ( not kidding, that is in the list of things ).
Other things have you checked you air filter as of late, or installed a FIPK. The reason I ask is if you knocked one of the lines loose from the intake, it is letting un mettered air into the system, and the truck is having problems compensating for it.
Try cleaning the MAFS ( do you also have pinging under load ?? ) and checking for cracks in the PCV lines behind the T/B ( yes it is a PITA, but it needs to be checked very closely ), before you go off checking other things on the list.
Let us know on the MAFS and PCV lines, as well as the other lines on the intake and the IAT also ( almost forgot that one ).
Here is the list from Ford.
DTC
P0174 - System to Lean (Bank 2) - see DTC P0171
DTC
P0171 - System to Lean (Bank 1)
Description
The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.
Possible Causes
Fuel system
Excessive fuel pressure.
Leaking /contaminated fuel injectors.
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel
Vapor recovery system.
Induction system:
- Air leaks after the MAF.
- Vacuum Leaks.
- PCV system.
- Improperly seated engine oil dipstick
EGR system:
- Leaking gasket.
- Stuck EGR valve.
Leaking diaphragm or EVR
Base Engine:
- Oil overfill.
- Cam timing.
- Cylinder compression.
- Exhaust leaks before or near the HO2Ss.
Diagnostic Aides
A SHRTFT-1,2 PID value between -25% to +35% and a LONGFT-1,2 PID value between -35% to +35% is acceptable. Reading beyond these values indicate a failure.
Thread Starter
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Member
Joined: Jun 2002
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From: Florida
Well its been 150 miles so far and no recurring CEL yet. It seems after the injector cleaner ( not walmart stuff) that it is back to idling normally again. Im hoping that the problem was just contaminated injectors. I have received great advice from this forum as to what else to look for. Seems i got better diagnoses from the forum here than i did from my shop i have used for 15 years.
Dave
Dave
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Member
Joined: Jun 2002
Posts: 72
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From: Florida
Well, I guess i spoke one day too soon
. About 170 miles the SES light returned. I went to autozone and picked up some air intake and throttle body cleaner and sprayed the mafs with it. I reset the PCM and i guess time will tell 
I have recently removed a K@N so im wondering if that is the culprit. It seems alot of posts refer to that. I had never oiled it either.
. About 170 miles the SES light returned. I went to autozone and picked up some air intake and throttle body cleaner and sprayed the mafs with it. I reset the PCM and i guess time will tell I have recently removed a K@N so im wondering if that is the culprit. It seems alot of posts refer to that. I had never oiled it either.
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Thread Starter
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Member
Joined: Jun 2002
Posts: 72
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From: Florida
Thanks to those that helped!!!! You guys ROCK!!
Well it been almost 400 miles since i cleaned the MAFS and no SES light. I went ahead and changed the PCV hose just for good measure. The boot didnt look bad but what the hell. For 21.00 i figured it cant hurt. I am probably jinxing myself by writing this reply. I did have a minor rough idle driving thru Mcdonalds one day but the light didnt return. I dont know whats up with that. You guys saved me around 400.00. Thanks for the advice. You guys ROCK!!!! 
. And BTW no one here is a MFer as stated in one recent thread. How can anyone DIS free advice????
Dave
2000 F150XL SC 4X4 4.6L 3:31
Cat back exhaust
Autometer Tranny Gauge
Removed K&N
Auxilliary Tranny Cooler
Tekonsha Voyager Brake Controller
. And BTW no one here is a MFer as stated in one recent thread. How can anyone DIS free advice????Dave
2000 F150XL SC 4X4 4.6L 3:31
Cat back exhaust
Autometer Tranny Gauge
Removed K&N
Auxilliary Tranny Cooler
Tekonsha Voyager Brake Controller
Technical Article Contributor
Joined: Jun 2002
Posts: 10,511
Likes: 10
From: Under the flightpath of old ORD 22R
David,
If the rough idle continues, look at cleaning the IAC. This is what makes sure that air gets around the closed butterfly to keep the engine running. It is the cylinder looking thing on the back of the T/B
Soapy water and a tooth brush, let dry good, bolt it back up.
Post on cleaning the IAC, and no it is not in the same place on a N/A engine, it is on the back of the T/B
https://www.f150online.com/forums/sh...&postid=839854
I seem to be having a IAC cleaning morning here, so take it with a grain of salt. 2 posts within 5 min both seem to be IAC problems. Maybe not....? Just something to keep in the back of your mind if it continues.
As for being a MF, I've been called that before, imagine what he is like if he doesn't get what he wants when paying for something if he calls people a MF for not giving free advice ?
If the rough idle continues, look at cleaning the IAC. This is what makes sure that air gets around the closed butterfly to keep the engine running. It is the cylinder looking thing on the back of the T/B
Soapy water and a tooth brush, let dry good, bolt it back up.
Post on cleaning the IAC, and no it is not in the same place on a N/A engine, it is on the back of the T/B
https://www.f150online.com/forums/sh...&postid=839854
I seem to be having a IAC cleaning morning here, so take it with a grain of salt. 2 posts within 5 min both seem to be IAC problems. Maybe not....? Just something to keep in the back of your mind if it continues.
As for being a MF, I've been called that before, imagine what he is like if he doesn't get what he wants when paying for something if he calls people a MF for not giving free advice ?