Starting trouble

Asked by 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

13,035

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

Ford F-150 Experts

  • #1
    OJ
    Reputation
    8,970
  • #2
    dandyoun
    Reputation
    4,550
  • #3
    tennisshoes
    Reputation
    3,070
View All

Related Models For Sale

Used Chevrolet Silverado 1500
2,073 Great Deals out of 165,976 listings starting at $1,900
Used GMC Sierra 1500
856 Great Deals out of 65,106 listings starting at $2,495
Used Ford F-250 Super Duty
349 Great Deals out of 44,658 listings starting at $1,799
Used Dodge Ram 1500
346 Great Deals out of 10,853 listings starting at $1,500
Used Toyota Tundra
428 Great Deals out of 32,056 listings starting at $1,999
Used Toyota Tacoma
630 Great Deals out of 42,613 listings starting at $1,500
Used Ford Mustang
678 Great Deals out of 37,871 listings starting at $895
Used Ford F-250
473 listings starting at $4,000
Used Ford F-350 Super Duty
329 Great Deals out of 24,220 listings starting at $2,488
Used Chevrolet Tahoe
673 Great Deals out of 39,482 listings starting at $1,000
Used Ford Explorer
832 Great Deals out of 63,644 listings starting at $1,000

Used Cars For Sale

2018 Ford F-150 For Sale
35,852 listings starting at $19,355
2017 Ford F-150 For Sale
126 Great Deals out of 77,269 listings starting at $17,989
2016 Ford F-150 For Sale
115 Great Deals out of 7,766 listings starting at $18,989
2015 Ford F-150 For Sale
308 Great Deals out of 10,858 listings starting at $15,995
2014 Ford F-150 For Sale
431 Great Deals out of 13,875 listings starting at $10,995

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.