Starting trouble

Asked by Robert Apr 29, 2016 at 03:54 PM about the 1999 Ford F-150 Lariat Extended Cab LB

Question type: Maintenance & Repair

I just replaced the EGR Pressure Sensor. Now my
truck has trouble starting, but, only after it has
been off for a while. There aren't any errors on the
dash. Once it has started, it runs fine and will
restart without a problem.

1 Answer

42,415

The DPFE measures the pressure difference across the orifice and sends the result to the computer. The p0401 code is lack of or low flow on a test the computer requests at startup and once during each drive cycle. The blockage likely is in the intake manifold behind the EGR valve. All you need to do to check this is apply vacuum to the EGR valve just enough to open it. If the port is open, the motor will stumble and run rough while idling as the indication it's open.If this check failed, you would have not needed to replace the DPFE but there is always a chance the DPFE needed replacement from accumulations you found. This system has to work with contaminated exhaust at all times. Have it read for codes,AGAIN even if the check engine light is NOT on the computer will have stored information and codes. Discount auto stores will read codes for no fee. Write them down. DPFE Delta pressure feedback emission

Your Answer:

CarGurus Experts

  • #1
    OJ
    Reputation
    42,510
  • #2
    Gene Arnett
    Reputation
    16,040
  • #3
    Rowefast
    Reputation
    15,860
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Chevrolet Silverado 1500
195 Great Deals out of 5,967 listings starting at $2,975
Used GMC Sierra 1500
143 Great Deals out of 7,206 listings starting at $3,950
Used Ford F-250 Super Duty
24 Great Deals out of 1,201 listings starting at $8,995
Used Toyota Tundra
34 Great Deals out of 1,190 listings starting at $8,500
Used Toyota Tacoma
57 Great Deals out of 1,080 listings starting at $8,708
Used Dodge RAM 1500
4 Great Deals out of 73 listings starting at $4,000
Used Ford F-250
6 listings
Used Ford Mustang
65 Great Deals out of 1,258 listings starting at $4,995
Used Ford Ranger
21 Great Deals out of 1,523 listings starting at $2,888
Used Chevrolet Silverado 2500HD
18 Great Deals out of 1,279 listings starting at $9,990
Used Ford F-350 Super Duty
35 Great Deals out of 2,591 listings starting at $8,888
Used Ford Explorer
87 Great Deals out of 2,048 listings starting at $2,999

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.