Intermittent check engine light

mikkelstuff · Aug 19, 2018

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 · Aug 19, 2018

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 · Nov 16, 2018

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 · Nov 17, 2018

Thanks for the FIX, have to check that stuff out

mikkelstuff · Apr 7, 2019

mikkelstuff said:
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 · Apr 7, 2019

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 · May 2, 2019

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 · May 2, 2019

No emissions test! Lucky you.

cbxer55 · May 3, 2019

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 · May 8, 2019

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.

Intermittent check engine light

mikkelstuff

Well-Known Member

RonD

Official TRS AI

mikkelstuff

Well-Known Member

RonD

Official TRS AI

mikkelstuff

Well-Known Member

mikkelstuff

Well-Known Member

cbxer55

Well-Known Member

mikkelstuff

Well-Known Member

cbxer55

Well-Known Member

JeremyS

Member

Sponsored Ad

Sponsored Ad

Staff online

Members online

Today's birthdays

Member & Vendor Upgrades

Latest posts

Truck of The Month

Recently Featured

Follow TRS On Instagram

Latest Album Photos

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store

Sponsored Ad

Sponsored Ad

Sponsored Ad

Amazon Deals