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Ask Chris (aka- Moose) Your Own Question
Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 47968
Experience:  16 years experience
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2003 Ford F-150 4.6 V8 stalls at times and shows trouble codes

Customer Question

2003 Ford F-150 4.6 V8 stalls at times and shows trouble codes for #5 missfireand codes for lean rt & Lt banks...Ford service replaced #5 coil pack & plug,EGR valve, fuel filter (fuel pressure ok im told)EGR control unit, TPS, And IAC unit!...$750 spent and still same 3 trouble codes showing at independent shop.Any idea??
Submitted: 2 years ago.
Category: Ford
Expert:  Chris (aka- Moose) replied 2 years ago.
Hi Have you done the common checks for lean codes. Testing the MAF sensor and checking for vacuum leaks. This engine is known for leaking PCV hose above the passenger valve cover. Has the compression and injector and injector signal and coil signal been checked on cylinder 5. You want a excellent 5 star answer & I would like to be rated the same for providing it. Consider I don't know your skill level & I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies. Try your best to respond with good detail so I can do the same. I normally log in at 3pm and work late. A rating is required. Your rating me, what I type. I am not an employee of this website, nor have control over the fees or the time it took to get a response. If you rate negative or not at all you still paid, but I get nothing. I want you pleased with me and my efforts, so let me know if your experience here has come up short.Thanks Chris
Customer: replied 2 years ago.
Hi Moose...Thanks for your quick reply. Can you steer me to the vacuum schematic for the PCV hose & valve. Is it attached to the center of the left Valve Cover? Also forgot to state that I did notice a large RPM increase if I induced propane near the left rear engine compartment but can see where it may have a vacuum leak without some teardown. So provide me with that schematic and I will go from there.
Expert:  Chris (aka- Moose) replied 2 years ago.
The Ford vacuum diagram is a drawn image like a wire diagram, it looks nothing like the vacuum hoses nor engine. Yes there is a PCV hose going to both valve covers to the intake manifold. Would the valve cover removal steps help, it does show the PCV hose in some detail. There is definitely a leak since the rpms increased with throttle.