2003 Ford Expedition has no power

Tiny
PICKUPGRL1027
  • MEMBER
  • 2003 FORD EXPEDITION
  • 4.6L
  • 2WD
  • AUTOMATIC
It started off where it would shut off but would start right back up but when you hit the gas it had no power it would not go. Now after I replaced the fuel pump, mas airflow sensor, plugs and cops it still has no power but starts and idles. What could it be please I have tried everything.
Sunday, January 4th, 2015 AT 2:20 PM

6 Replies

Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
WHEN IT WAS RUNNING, WAS THE IDLE NORMAL?

IS THE CHECK ENGINE LIGHT ON?

HAVE YOU HAD CODES RETRIEVED?

IF SO, WHAT ARE THE CODE NUMBERS?

HAVE YOU SEARCHED FOR VACUUM ISSUES, HOSE OFF/ CRACKED HOSE/ ETC?

NEED MORE INFO ON HOW OR WHAT TO DO?

THE MEDIC
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Sunday, January 4th, 2015 AT 2:36 PM
Tiny
PICKUPGRL1027
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  • 4 POSTS
Yes the check engine light was on. It is missing on the first cylinder. Is all the machine showed. I have checked all hoses. Please help me
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Sunday, January 4th, 2015 AT 2:43 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,834 POSTS
Hi guys. I can add a few suggestions. First, consider a plugged exhaust system, in particular, the catalytic converter. If it is restricted, you'll hear more of a hiss from the tail pipe instead of the normal "putt putt" sound. Idle will be very good but the engine will usually tend to run hot.

Also look at the EGR system. I don't know if this applies to your engine and year, but Ford has had a real common problem with the EGR tubes becoming plugged with carbon. The confusing part is that when the tube to one cylinder gets plugged, that cylinder runs fine because all it's getting is fuel and fresh air. 100 percent of the exhaust gas flow is split evenly among the remaining cylinders. Eventually all but one tube become completely plugged, so 100 percent of the EGR goes to the one remaining cylinder. There's not enough fresh air to support combustion, so the only cylinder with a clear EGR tube is the one that misfires.

EGR doesn't occur at idle so the symptoms won't be noticed there. At higher speeds a single-cylinder misfire is harder to feel, but the Engine Computer will still detect it, and it will obviously cause a loss of power.
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Monday, January 5th, 2015 AT 6:11 PM
Tiny
PICKUPGRL1027
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We checked the converters and the EGR is clean and so are the hoses. See the truck don't have enough power to move it a little bit. I don't understand how it can do that but after I replaced the mass airflow sensor it ran great for 15 mile s then did it again I am at a loss somebody help me. LOL
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Monday, January 5th, 2015 AT 6:27 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,834 POSTS
CJ mentioned diagnostic fault codes. Usually when you have a single-cylinder misfire code, there will be another one related to the cause. Check that first.

If there's no other codes, you'll need a scanner to view live data while the engine is running. An experienced engine performance mechanic can tell from sensor data whether the cause is related to fuel, air, spark, and even compression. I'm not that good when it comes to interpreting that information, but I've seen them do it.
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Monday, January 5th, 2015 AT 6:38 PM
Tiny
PICKUPGRL1027
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OK ty. I am just confused is all my brother is a mechanic and it has him puzzled. Even though he only works on Chevy's. LOL.
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Monday, January 5th, 2015 AT 6:42 PM

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