I own a 2001 super crew 4x4 5.4 liter (103,000 mi). The check engine light is on. computer scan shows it to be running rich on both banks. Anyone here have any clue what might be the cause.

On a another note I have been through six coils. Does anyone know what causes these to fail?

Thanks in advance!

 

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Welcome to the forum

Do you know the actual codes that were recieved and not just the description?
The problem could be caused by a bad or dirty MAF sensor, fuel pressure regulator, O2 sensors etc. The actual code would help us narrow it down.

 

It is not showing any other codes, only "rich both banks". Local Ford tech says he never encountered one like this before. Tests of the sensors show everthing is normal.

 

Did the tech do any diagnosing or did you just ask him about it?
Sometimes us techs get real problem jobs that are almost impossible to figure out but usually, eventually we'll fix them
I would start by checking the fuel pressure and monitoring live data for the O2s, MAF, fuel trims and injector pulse width etc. Something out of the ordinary should show up.

 

Racerguy,
He monitored the live data and couldn't find anything out of the ordinary. Engine seems to run ok. Just the check engine light keeps coming on.

Thanks for your input

 

Did he clear the codes after he retrieved them?
If he did and they came back he really should be able to find something.
If he didn't clear the codes to turn the light off you can do that by yourself by disconnecting a battery cable for 10 minutes.

 

Codes were cleared every time. Each time the "Check Engine" light comes on within 20 minutes of drive time. Sensors tests reveal nothing out of the ordinary.

Here is a brief history of my engine troubles.
At approx. 45,000 miles, engine develops a miss. Check engine light does NOT come on. Local mech. (not Ford dealer) tries to scan computer to no avail.
Computer does not sense the miss, which very pronounced. Mech. says it is more than likely a coil, but w/o a code cannot pinpoint which cylinder is missing.
He sends me to local Ford dealer whose is able to find the problem coil (engine light never did come on).
This happens four more times to four more coils and the Check Engine light never did come on.

At approx 101,000 miles another miss develops and I am also getting hard starts, engines puffs smoke on start up, Check Engine light finally comes on. Back to Ford dealer who changes another coil. Engine runs fine at dealership and I don't get 20 miles down the road when it starts missing again and check eng. light comes on again.

Dealer finds problem with a fuel injector (dirty), changes injector and hard starts go away (says it was allowing too much fuel to flow into the cyl.) Several days later Check engine light comes on again and you know the rest of the story.

 

How many miles on the spark plugs?
What color is the smoke on start up?

 

Smoke seemed to be dark gray, not as light colored as mostly oil tends to burn.
approx. 65K on plugs. (I changed them when engine first missed) later found it was a coil.

 

With 65K on the plugs I'd be replacing them. What brand of plugs did you use?
I would also check the fuel pressure to make sure it's not too high due to a bad regulator.

 

Check your ecu. Mine was throwing weird codes before I replaced it.

 

I'll change out the plugs, can't recall what I put in it the first time. Most likely Motorcraft or AC. And check the fuel pressure if he hadn't checked it already.

ECU?? I am a newbie to all this sensor stuff, I remember $0.22 gas and points!

Thanks for the help guys, I really appreciate it!

 

ECU=ElectronicControlModule aka the brains of the outfit also called PCM=PerformanceControlModule. I had to buy a new PCM for my 97 at about 85,000mi. The engine had been running rough and never threw a code for over a year. By pulling the coil wires we found it was #1 every time but a new coil and plug never helped. Finally my mechanic buddy pulled the PCM and cracked it open (voids warranty) and found the #1 connection on the board was burnt thru. There was lots of black carbon everywhere so it had been arcing and causing trouble for a long time. Hope that's not your problem tho cause it cost me $500.