P0171 and P0174

[sassee]

Help!

My wife's Sport-Trac has the CEL coming on, scanner showing codes P0171 & P0174. (Lean in Banks' 1 and 2). I just did scheduled oil/oil filter/air filter/fuel filter change this weekend. Reset light just for the heck of it and drove out of town shopping and CEL did not come back on until later that night (After approx 60 miles or so). I do not notice any issues while driving, it's runs fine. HOWEVER, when the car is parked, tranny in PARK, it's starts to skip around 2500 rpm's when you rev it up??? It appears the only skip is when revving it up in PARK since it ran fine driving Saturday evening.(I passed a few cars just to test) The idle seems normal. (not idling high or i would be looking for a vacum leak) Of course, it could very well still be getting too much air from somewhere, i just don't know where the most probable locations are. Any HELP appreciated.

[shorod]

What year is the Explorer, and which engine does it have?

Many of the newer vehicles have an overrev limiter to prevent you from overrevving the engine in Park or Neutral. That's probably what's happening when you rev the engine while in park.

The Differential Pressure Feedback EGR (DPFE) is a pretty common culprit for the P0171 and P0174 codes. Use the "Search this forum" feature from the Explorer forum main page to find other potential causes of these codes. The search feature should be everyone's first check on these forums!

-Rod

[sassee]

Sorry!

It's the 4.0 V-6, NON-Flex fuel.

I did do a forum search before posting but the skipping/cutting-out when I revved it up wasn't in any thead that I read. I thought it may have some significance so i posted it.

[sassee]

Where is the DPFE on my 2003 Sport-Trac? Does this part have any aliases??? Auto-Zone and Advance Auto show an "EGR Valve Pressure Sensor". Is this the same item? From the pic, it looks like it has a plastic body, two plugs for hoses and what appears to be a 3-throng electrical/electronic connection.

On the drive home from work yesterday I noticed the idle is starting to get a little choppy. Could the DPFE by the source of all my troubles? No other CEL codes, just the initial P0171 and P0174 (Lean Banks 1 & 2).

[shorod]

That would probably be it. I don't know specifically where it will be located on your 2003.

Which of the 4.0L V-6 engines does your wife's Sport Trac have? I can check my service manual for the 2002 model year. It should be pretty similar to your 2003.

-Rod

[sassee]

The engine is the 4.0 V6, Vin code "E", Non-Flex Fuel.

I found the location. It's sitting right there on top of drivers side valve cover. The EGR Valve Pressure Sensor IS the DPFE! Only problem is the sensor that Auto Zone shows for my truck IS NOT THE SAME AS WHAT IS ON IT?. Not even close, different size, different electrical connector,,etc Any clue as to where to buy one? (other than Ford Dealer)

[sassee]

' just went and bought the DPFE from local Ford Dealer ($124...ouch) just put it on and reset computer. Will let you know how it does.

[sassee]

CRAP!

Light came back on!

[shorod]

These are the items the service manual recommends considering for a P0171 and P0174 code. Keep in mind that you're likely looking for something that would affect both cylinder banks in a lean way, so some of these won't apply:

• -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 HO2S

-Rod

[sassee]

I put some Lucas Injector Cleaner in it this AM and have ran it doing errands all morning. It never ran bad before, just the idle went south the other day. It's idling fine now and as long as the idle stays good, I'll run it with the light on. I'll go thru and check item by item when I have more time to do so.

[sassee]

MAYBE THIS WILL HELP!!!!

****Just checked it little while ago................

I checked for vacuum leaks with can of carb cleaner, checked around intake gaskets, fuel rail, fuel pressure regulator, etc. Did not find any noticeable difference. I had cleared codes last night but I put scanner on this and got 5 codes (AND THE CHECK ENGINE LIGHT WAS NOT ON!)

P0171 Same as before

NEW CODES

P2195 (Bank 1 Sensor 1 O2 Stuck Lean)
P2197 (Bank 2 Sensor 1 O2 Stuck Lean)
P0300 Random Multi fire detected
P0316 Forgot, some kind of misfire detected

IS THIS THING POSSESSED! i'M ABOUT READY TO SEND IT TO THE USED CAR LOT! WITH ALL OF THE DIFFERENT CODES POPPING UP,IS THIS A FUEL PRESSURE PROBLEM? WHERE DO YOU HOOK-UP A FUEL PRESSURE TESTER ON THIS SPORT-TRAC? MY SUBURBAN WAS EASY.................THE SCHRAEDER VALVE WAS ON THE FRONT IN PLAIN SITE. I CAN'T FIND ANY PLACE TO HOOK UP TO ON THE SPORT TRAC

[sassee]

Uhhh..............

Any help appreciated!

[shorod]

P0316 is indicating that a misfire occured in the first 1000 engine revolutions. According to the factory service manual, this could be due to the following:

• Damaged Crankshaft Position Sensor (CKP)
• Ignition system
• Fuel injectors
• Running out of fuel
• Fuel quality
• Base engine
• Damaged PCM

Code P0300 would potentially be caused by:

• Camshaft position sensor (CMP)
• Low fuel (less than 1/8th tank)
• Stuck open EGR valve
• Blocked EGR passages

P2195 and P2197 being lean codes, it would seem the common cause to be low fuel/low fuel pressure.

I would have expected there to be a Shrader valve on the fuel injector rail as well. It's not there?

-Rod

[sassee]

I didn't see the schrader vavle but I feel there HAS to be one somewhere, i'll keep looking. Based on what the "book" is saying, the common denominator seems to be low fuel pressure.

What should the idle fuel pressure be on the truck? (2003 Sport-Trac, 4.0 Vin Code "E" engine) I'll check the pressure this evening.

What's really weird now is the 5 codes came up on the scanner after I cleared previous P0171 & P0174 codes and the Check Engine Light never came on! I left the scanner plugged in and noticed the codes when the idle started going south. Since the problem is not a CONSTANT bad idle, the fuel pump may be on it's last legs. I've just never had one do this before. It has either worked or it didn't.

ALSO, could the fuel pressure regulator be a culprit?

[shorod]

The fuel pressure should be 65 +/- 8 psi.

How steady does the fuel pressure remain during idle as well as when the engine speed is increased or blipped?

-Rod