Intermittent check engine light

[mikkelstuff]

I've been getting an intermittent check engine light for the last 6 months with my 2002 Ranger XLT 3.0L (130,000 miles). The OBD analyzer indicates a miss in cylinder number 4 but, if so, I never notice it. The check engine light stays on for a week or so and then goes off.

I have replaced the spark plugs, plug wires (with Motorcraft set), and cam synchronizer (Motorcraft) all in the last 3 years and 10,000 miles. I have not touched the fuel injectors other than to try a can of Seafoam.

I pulled the number 4 cylinder spark plug but it looks clean and properly gapped.

The check engine light came on more often over the winter but has become more frequent of late. Any idea as to what causes this?

 

[RonD]

Reads like you may have a vacuum leak on lower intake by #4, I would check tightness of lower intake bolts if possible, just snug them up.

Reason is you mentioned CEL coming on more often in winter, and cold air makes small vacuum leak more likely to cause an issue, cold air is denser so more fuel is needed.

You can also try spraying soapy water around that area with engine running, engine will stumble if any is sucked in.
This is safer that flammable sprays, but your choice


Reverse #3 and #4 spark plug wires on the coil pack.
Ford use Waste spark system so 3 and 4 both spark at the same time, but each is reverse spark from the other, so coil pack can cause spark issue on one and not the other, and it is FREE to try
If misfire code change to #3 then replace coil pack

Was the code P0304?

 

[mikkelstuff]

I finally fixed this annoying problem. At the suggestion of my cousin's husband, a truck mechanic, I gave it a can of BG-44K fuel injector cleaner. I've run several tanks of gas through it and no more engine warning lights!

I'd tried Seafoam injector cleaner to no avail but the BG-44K, rather expensive by comparison, did the job. Great stuff!

 

[RonD]

Thanks for the FIX, have to check that stuff out

 

[mikkelstuff]

I've been getting an intermittent check engine light for the last 6 months with my 2002 Ranger XLT 3.0L (130,000 miles). The OBD analyzer indicates a miss in cylinder number 4 but, if so, I never notice it. The check engine light stays on for a week or so and then goes off.

I have replaced the spark plugs, plug wires (with Motorcraft set), and cam synchronizer (Motorcraft) all in the last 3 years and 10,000 miles. I have not touched the fuel injectors other than to try a can of Seafoam.

I pulled the number 4 cylinder spark plug but it looks clean and properly gapped.

The check engine light came on more often over the winter but has become more frequent of late. Any idea as to what causes this?

 

[mikkelstuff]

Despite all my efforts, I have not been able to isolate this intermittent check engine light problem which might reappear after an hour or after a few weeks.

Now I always use non-enthanol gasoline which is only available locally at the Walmart Murphy Express. However, I hate that gas station which is always crowded with rude folk cutting into line, etc.

So lately, I have been refilling at a Maverik gas station 15 miles away which also carries non-ethanol gas and, much to my amazement, I have not had one single check engine light ever since.

Who knows? This could be the answer.

 

[cbxer55]

With these old trucks, the answer is as simple as a piece of black tape on the dash covering the area the CE resides in. I removed the EGR valve on my 98 and so the CE is always on. Piece of black tape fixes it and it runs super great. SO I don't give a d--- about the CE. No emissions or safety checks here, so no big deal.

 

[mikkelstuff]

No emissions test! Lucky you.

 

[cbxer55]

2002 Ranger. Doesn't your state allow a certain number of imperfections due to the age? Most allow one or two monitors to be INC. Also a default code or two is allowed. I know here, most Lightning owners have the EGR and the cats deleted. I'm planning on doing that to my Lightning this year, already have two of the cats deleted. Factory had four, mine has two high flows. May leave it like that since once the cats are totally deleted, they can be LOUD. I like hearing my supercharger whine, so a louder exhaust than what it already has is not really ideal.

 

[JeremyS]

Have you noticed any misfires, especially while at idle? I was chasing a #5 cylinder misfire last year that ended being a bad exhaust valve seat. A compression check would identify if you have this issue.