Code Error Read List
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Thanks for the help.It' a 1997 F150 4X4 ,4.6. auto trans. speedometer quit a few months ago at 168,000 miles.
Issues include: No speedometer, OD light continuously blinks and has started misfiring at Idle and on Hwy.
codes showing up are: P0500,P0401,P0304,P0308,P0174
Plugs were changed approx 20,000 miles ago. I've unplugged all injectors one at a time. all cyl fire but a few are weaker than others. Trans goes into OD, just light blink, it shifts hard but I figure has to do with the other problems.
Issues include: No speedometer, OD light continuously blinks and has started misfiring at Idle and on Hwy.
codes showing up are: P0500,P0401,P0304,P0308,P0174
Plugs were changed approx 20,000 miles ago. I've unplugged all injectors one at a time. all cyl fire but a few are weaker than others. Trans goes into OD, just light blink, it shifts hard but I figure has to do with the other problems.
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Joined: Jun 2009
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From: Fort Smith, Arkansas
Thanks for the help.It' a 1997 F150 4X4 ,4.6. auto trans. speedometer quit a few months ago at 168,000 miles.
Issues include: No speedometer, OD light continuously blinks and has started misfiring at Idle and on Hwy.
codes showing up are: P0500,P0401,P0304,P0308,P0174
Plugs were changed approx 20,000 miles ago. I've unplugged all injectors one at a time. all cyl fire but a few are weaker than others. Trans goes into OD, just light blink, it shifts hard but I figure has to do with the other problems.
Issues include: No speedometer, OD light continuously blinks and has started misfiring at Idle and on Hwy.
codes showing up are: P0500,P0401,P0304,P0308,P0174
Plugs were changed approx 20,000 miles ago. I've unplugged all injectors one at a time. all cyl fire but a few are weaker than others. Trans goes into OD, just light blink, it shifts hard but I figure has to do with the other problems.
P0401 is low EGR flow.
P0174 system too lean which is almost always a vacuum leak on bank 2 (driver side). Many times the vacuum leak is actually on both sides but only one side has reached the threshold for reporting the code due to uneven O2 sensor degradation. Make sure all the air cleaner tubing is tight and leak free.
P0304 is misfire on cylinder 4, P0308 is misfire in cylinder 8. Since these are both the rear most plugs one on each bank, it is likely that either someone skipped replacing these plugs because they are the most difficult to reach or there has been water intrusion into the plug holes. Pull off the plug wire boots for those cylinders and blow out the spark plug holes with compressed air. If you don't know when the spark plugs were changed last then they are probably past due. This may be a good time to get those changed along with plug wires.
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When I got the truck I was told pluges had about 20,000 miles on them. Guess it's likely he was lazy and didn' replace 4 and 8. I'll try replacing plugs and clean the EGR valve.
Thanks, you helped a lot
Thanks, you helped a lot
Lead Driver
Joined: Sep 2006
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Your truck needs to be gone over for many issues due to its age.
The codes you have are expected from age and lack of maintenance.
20k mileage on plugs does not disqualify them from misfire problems.
You have plug wires and boots that can be the issue plus the coils.
The 401 code could be blocked ports behind the EGR valve.
VSS a harness or sensor issue.
Good luck.
The codes you have are expected from age and lack of maintenance.
20k mileage on plugs does not disqualify them from misfire problems.
You have plug wires and boots that can be the issue plus the coils.
The 401 code could be blocked ports behind the EGR valve.
VSS a harness or sensor issue.
Good luck.
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I bought the truck from a construction company. Maintenance was probable not a top priority. I,m working on a tight budget. here is what I've done today. I replaced #8 plug(didn't look fowled or burnt),plug wire and removed EGR and cleaned it. Only thing I saw with EGR was vacuum line broke when removed.Now runs better still with smaller miss.Tomorrow I will try to borrow code reader again and go from there.
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the broken vacuum hose would cause the 174 code and it could make the EGR non functioning and cause that 401 code....... You need to clear all the codes NOW... with the code reader, or pull off positive cable on battery for a minute... reinstall... run truck for 30 minutes... then read NEW codes.
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Thanks Steve, I've pulled positive cable off and clear all the codes. Now I have to find the guy I borrowed code reader from to be able to read new codes or when I go to town I'll go by AZ or O'Reily, get them to read them
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