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 1,920
#2 Larry Sturgis
Larry Sturgis
Reputation 1,360
#3 lightGear
lightGear
Reputation 1,030
View All

Related Models For Sale

Used Ford Explorer
912 Great Deals out of 63,241 listings starting at $700
Used Chevrolet Tahoe
597 Great Deals out of 33,197 listings starting at $1,375
Used Chevrolet Suburban
273 Great Deals out of 19,342 listings starting at $1,999
Used Lincoln Navigator
90 Great Deals out of 5,590 listings starting at $1,900
Used Ford F-150
2,086 Great Deals out of 191,511 listings starting at $290
Used GMC Yukon
437 Great Deals out of 20,488 listings starting at $1,495
Used GMC Yukon XL
215 Great Deals out of 12,587 listings starting at $1,495
Used Cadillac Escalade
190 Great Deals out of 10,926 listings starting at $2,500
Used Toyota Sequoia
129 Great Deals out of 5,309 listings starting at $2,500
Used Nissan Armada
134 Great Deals out of 9,024 listings starting at $2,991
Used Ford Excursion
9 Great Deals out of 800 listings starting at $1,999
Used Dodge Durango
274 Great Deals out of 20,980 listings starting at $1,500
Used Ford F-250 Super Duty
326 Great Deals out of 43,857 listings starting at $1,450
Used Toyota 4Runner
228 Great Deals out of 19,339 listings starting at $2,300

Used Cars For Sale

2017 Ford Expedition For Sale
29 Great Deals out of 14,375 listings starting at $26,995
2016 Ford Expedition For Sale
128 Great Deals out of 1,700 listings starting at $25,991
2015 Ford Expedition For Sale
18 Great Deals out of 586 listings starting at $19,995
2014 Ford Expedition For Sale
37 Great Deals out of 752 listings starting at $14,995

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.