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I have a 2000 Taurus with the 24V DOHC Duratec motor w/216K and i keep getting P171 & P174 and am tired of replacing parts. When i start the car cold it stumbles up and down and i rev it at 2000rpm for about a minute and it calms down a bit, but still stumbles at idle until it is warm. Once it has fully warmed up, the stumbles go away pretty much but it still has an occasional hesitation at idle and then throws the code.
I think i had this error once before constantly and replaced the EGR valve, DPFE sensor, and voltage regulator and it went away. Has someone with this duratec motor in the Taurus or Escape ever got these codes and what fixed the issue?
PARTS REPLACED & OTHER THINGS DONE SO FAR:
-Cleaned MAF with electronics cleaner
-Tried my old Motorcraft EGR valve and replacement BWD EGR Valve
-2 different EGR voltage regulators and doesnt help
-New throttle body gasket
-New Intake manifold gaskets for the plenum (6)
-PCV rubber hose is fine
-EGR gasket is fine
-Have went through a couple of BWD brand Idle Air control Valves, some rev too low and some rev to high, so i might try a motorcraft one next
-Have replaced the spark plugs
-Cleaned the throttle body plate
-Changed Air Filter
-PCV valve was replaced 2 yrs ago
- I leak oil, but have been leaking for a while now ( might be oil pan or valve cover)
-Replace the back 3 Ignition Coil Plugs...the front 3 may be next
instead of throwing parts at the problem, get a shop manual and look up the codes, and follow the testing instructions for each code. remember that the computer code thrown only tells you what system is being affected, not what part is faulty.
Fords engines are extremely finicky about the parts used in the PCV system. Get all of the parts back to Motorcraft so you have a start place. The issue is you have too much air in the intake system that the PCM can't account for. Probabilities are high that it's a simple vacuum leak. Check all vacuum lines and inspect closely any in the PCV system. Find the vacuum leak and this will go away.
instead of throwing parts at the problem, get a shop manual and look up the codes, and follow the testing instructions for each code. remember that the computer code thrown only tells you what system is being affected, not what part is faulty.
I have a Code scanner, and ive looked up the codes which are the same says its running too lean. Ive replaced just about everything that relates to those issues.
I have a Code scanner, and ive looked up the codes which are the same says its running too lean. Ive replaced just about everything that relates to those issues.
big deal, i said look up the TESTS that are indicated in the shop manual for each code. just looking up the codes and what they are for only tells you what system is being affected, not what parts are the problem.
and as GarageLogic indicated you may have a vacuum leak, but until you run the specified tests you wont know if it is a vacuum leak, a bad connection, or a bad sensor, or other issue. you can continue to throw parts at the problem and hope that something cures it, or you can run the indicated tests.
I know from experience when P0171/P0174 pop up on a similar year F150, the PCV valve hose is usually at fault. Just because you think it is fine, does not mean there are not tiny cracks in that hose--especially around any bends--that crumble after that kind of mileage. You should replace that hose, anyway.
You did get the intake plenum gaskets, which is also something I did with my lean codes, but I also had isolator bolts/o-rings to replace as well. Problem solved.
You may want to be looking into changing all intake gaskets on both upper and lower plenum if you haven't done them all.
Vacuum leak - most likely at your intake manifold gaskets or, like someone else mentioned, at the bolts. Make sure your bolts have the correct torque applied too.
Thanks for the posting. I have a 2001 Sable. Same motor. Same description of problems. Thinking about doing this over the weekend.
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