Problem with a 2000 expedition

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MAKE: ford
MODEL: expedition
YEAR: 2000
MILES: 189,000
DESCRIBE ISSUE....hello everyone,
I have a 2000 expedition with a 5.4 and the problem is a high idle and runs ruff. About a years ago the check engine light came on and the codes were something about ignition coils and o2 sensors, so I replaced all of them. Then about three months ago I started getting these codes, p0155, p0135, p0153, p1151, p0113.
I have replaced the PCV valve and rubber elbows and cleaned the throttle body and iac, I have checked for vacuum leaks over and over and can’t find any. So two weeks ago I thought ok I had a bad o2 heater so I replaced them again and the same thing. The runs but ruff and when you start it it runs at 2000-2200 rpms and it might take 30 seconds to go down to 1000-1200 making it really hard to drive and very very poor fuel mileage. It used to get 16 mpg and now around 8 or 9.
Hopefully someone has some ideas please
I did read this morning the a maf sensor can cause these codes to ? I took it apart and it is clean?
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You listed p0113 I guessed you mistyped P0131 - yes?

Vehicle is STOCK - no BS ie K&N type filter?
Are there ANY other codes or issues?
Did you use cheap wire yourself o2 sensors?
loosing coolant?
Exhaust leak?

I see a wiring issue at sensors would cause the majority of codes -

P0131 (5.4L V8 VIN L Auto) HO2S-11 (Bank 1 Sensor 1) Circuit High Input
P0135 (5.4L V8 VIN L Auto)HO2S-11 Heater Circuit (Bank 1, Sensor 1)
P0153 (5.4L V8 VIN L Auto)HO2S-21 (Bank 2 Sensor 1) Circuit Slow Response
P0155 (5.4L V8 VIN L Auto)HO2S-21 (Bank 2 Sensor 1) Heater Circuit Malfunction
P1151 (5.4L V8 VIN L Auto)Lack of HO2S-21 Switching, HO2S Signal Low Input

P0113 FORD Description The Intake Air Temperature (IAT) sensor is built into mass air flow sensor or in some vehicles mounted to the air filter duct housing. The sensor detects intake air temperature and transmits a signal to the Engine Control Module (ECM).The temperature sensing unit uses a thermistor which is sensitive to the change in temperature. Electrical resistance of the thermistor decreases in response to the temperature rise. The Intake Air Temperature signal is used as an input for various systems in the vehicle.
I looked at the manual for your scanner Innova 3020a and you do not have the capability to display live data. If you did, I would suggest that you compare temp readings between IAT and ECT sensors. When engine is "stone cold", both sensors should read (about) the same.
Read more:
OOPs thats what I get for guessing. Sorry for wrong avenue of thinking.

Dan correction to P0113 - suggests to me there could be more codes (p1116) will scanner read ALL codes those manufacturer specific P0999 and up?

The mention of a IAT and of MAF , I asked about K&N a POS often an issue with sensors.

Any gauge readings weird ECT especially or hard start in hotter or cooler temps - ideally a check like dan suggested live data ECT IAT if applicable EOT.


Wrench. I help when I can
I am noticing all the o2 codes are for upstream. That is telling you something.

Now that we now it is a IAT code, I would start by checking that codes first, disregard all others for now. Trouble shhoot the IAT code, erase all those codes and then see what comes back.

You will rarely if ever see both sensor fail on both backs at same time either up stream or down stream. So that is indicating you have a failure affecting both banks. Such as a vacuum leak, or in this case, a IAT/MAF sensor failure affecting both banks.

So my belief is that the best approach is as written above. Disregard the o2 codes for now, focus on the IAT.

That heater circuits codes will probably come back, that is easy to check, just check the internal resistance of that heater circuit and compared to its cousin on the other bank. Both should be same or very close to specs.

You will want to check the fuse. It may have blown. That should be fuse #23 15amp in BJB. Here are some wiring's and charts to help you along the way. Resistance of heaters should be in step H35. Screenshot (168).png Screenshot (169).png Screenshot (170).png Screenshot (171).png Screenshot (172).png


Wrench. I help when I can
Also, you will want to wiggle test the main engine harness, you may have a bad connection. Do while engine is operating at temp and notice any difference in engine character. Also, flex the air intake tube up and down, you may have a cracked inlet duct.


Wrench. I help when I can
Oh, and try to get your self a BT elm 327 dongle, at least with that you get live data. I would love to see the long and short fuel trims. You can get one for 20-30$ on line. Check it out. This is what you need to check your codes out. It displays all you need. Just read the data it display in this link I provided. It does more with the right software. Try a few free apps out. You might just thank me one day. Here is that link;)

Way better than that walamart code reader. Works with your smartphone or laptop. I prefer bluetooth, but it wont play well with a f-ing apple I-OS. I hate apple anyway, so I don't care. But granola eating, audi driving apple users are who they are, so they can pay more for a 327 dongle since they like paying more for their stuff anyway. I think those ppl just think it's cool to pay more. But is a whole other debate, and I certainly would not want to offend the granola eating ppl of this planet. :eek:;)
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I have a elm 327 but could not get it to work with my iPhone or laptop. I cleared the codes and they all came back within 15 minuets. I do need a good scanner something with live data, I am not one to just start replacing parts.
I would recommend a digital meter for the O2 IAT sensor circuit testing.

I would recommend a 12v test light for the O2 heater circuit testing.