P0171 P0420 P0430 - Little enging power - 03 Expedition

Asked by Feb 05, 2010 at 04:11 AM about the 2003 Ford Expedition

Question type: Maintenance & Repair

The 2003 Ford Expedition 4.6L 2WD idles fine when cold at about 1000 RPM, but upon warming the idle drops to 700 RPM.  When the throttle is past 1/3 the power flattens out.  The Freeze frame data from the past 5 times the Check Engine Light came on shows the following items (results side-by-side):

OBD2 P0 Codes 171&430 P0171 420&430 171&430 P0430 P0171
Fuel Sys1     CL CL CL CL CL CL
Fuel Sys2    NA NA NA NA NA NA
Calc Loan%     92.94 79.61 50.98 90.20 71.76 88.63
ECT (f)     89 89 90 92 90 94
STFT B1%     3.13 7.03 -6.25 5.47 -2.34 9.59
LTFT B1%     24.22 29.69 14.06 24.22 8.59 24.20
STFT B2%     0.00 1.56 -0.78 3.13 -4.69 -2.34
LTFT B2%     -12.50 -14.64 -9.38 -10.16 -9.38 -12.50
Eng RPM     2608 2970 1278 2723 1434 2621
Km/h     94 37 59 100 54 61
Spark Adv (0)   20 18 38 23 31 21
IAT (C)     6 18 7 17 21 15
MAF (g/s)     78.01 81.22 18.77 70.98 25.00 63.62
TPS (%)     61.96 45.88 22.35 56.08 27.45 49.40
O2S B1 S1(v)    0.75 0.10 0.87 0.14 0.80 0.09
STFT B1 S1(%)   3.13 7.03 -6.25 5.47 -2.34 8.59
O2S B1 S2(v)    0.79 0.12 0.82 0.21 0.72 0.25
STFT B1 S2(%)   99.22 99.22 99.22 99.22 99.22 99.22
O2s B2 S1(v)    0.76 0.90 0.76 0.11 0.26 0.78
STFT B2 S1(%)   0.00 1.56 -0.78 3.13 -4.69 -2.34
O2S B2 S2(v)    0.82 0.83 0.19 0.37 0.55 0.75
STFT B2 S2(%)   99.22 99.22 99.22 99.22 99.22 99.22

P0171  =  System too lean (bank 1)
P0420  =  Catalyst System Efficiency Below Threshold (Bank 1)
P0430  =  Catalyst System Efficiency Below Threshold (Bank 2)

I had just replaced a bad fuel pump and filter.  The two hoses going from the exhaust to the EGR EVP keep blowing out when under a full load, perhaps the catalytic converter is shot and is blocking the exhaust?

I put the new PCV valve on the wrong valve cover so it ran with two PCV valves and an extreme amount of vacuum for a while, not sure if that messed something up.

Any ideas on what is causing the problems would be appreciated.

Thanks!

John

1 Answer

10

sounds like the cats are plugged or there is a heavy restriction in the exhaust. unbolt the y-pipe and go for a drive and see if your power is restored. or you can use a back pressure guage to confirm the diagnosis. unfortunantly there are 4 cats on your vehicle. If it was my vehicle I would get the cats removed and install two O2 simulators.

1 of 1 people found this helpful.

Your Answer

Add photo

Related Questions

Search Ford Expedition Questions

Ford Expedition Experts

#1 T_S_T
T_S_T
Reputation 1,890
#2 Larry Sturgis
Larry Sturgis
Reputation 1,310
#3 lightGear
lightGear
Reputation 1,010
View All

Related Models For Sale

Used Chevrolet Tahoe
550 Great Deals out of 29,234 listings starting at $1,699
Used Ford Explorer
945 Great Deals out of 72,519 listings starting at $1,000
Used Chevrolet Suburban
323 Great Deals out of 19,720 listings starting at $2,000
Used Lincoln Navigator
118 Great Deals out of 5,791 listings starting at $1,900
Used Ford F-150
2,194 Great Deals out of 206,316 listings starting at $1,499
Used GMC Yukon
376 Great Deals out of 18,226 listings starting at $2,950
Used GMC Yukon XL
236 Great Deals out of 12,302 listings starting at $2,950
Used Cadillac Escalade
239 Great Deals out of 11,197 listings starting at $2,495
Used Toyota Sequoia
153 Great Deals out of 5,651 listings starting at $2,700
Used Nissan Armada
144 Great Deals out of 8,778 listings starting at $3,499
Used Ford Excursion
11 Great Deals out of 799 listings starting at $3,995
Used Dodge Durango
274 Great Deals out of 22,704 listings starting at $1,200
Used Ford F-250 Super Duty
346 Great Deals out of 46,938 listings starting at $1,895
Used Chevrolet Silverado 1500
1,717 Great Deals out of 175,749 listings starting at $1,250

Used Cars For Sale

2017 Ford Expedition For Sale
21 Great Deals out of 14,278 listings starting at $29,888
2016 Ford Expedition For Sale
130 Great Deals out of 2,317 listings starting at $25,799
2015 Ford Expedition For Sale
20 Great Deals out of 750 listings starting at $19,995
2014 Ford Expedition For Sale
39 Great Deals out of 832 listings starting at $17,950

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.