So the light started blinking and stayed on under hard acceleration. It's a 2008 f350 with 6.8. Truck didn't seem to be lagging in performance. Tomorrow I'll go to autozone and see what code it threw but first anyone have any experiences of what they did?

What does your owner's manual indicate?

I had an 86 Suburban that had the check engine light come on and then start blinking. I was coming home from snowmobiling on the NYS Thruway. I drove it the last 10 miles to my house. It was a malfunction in the distributor. It ended up needing both converters and all 4 O2 sensors because I kept driving it. Thankfully it had an extended warranty! A blinking check engine light is not a good thing.

Are you saying it started blinking and then settled into a steady light? If it kept blinking I wouldn't drive it until the fault is known. It means severe damage can occur to converters. Go buy a $30 code reader.

A solid check engine light means check the codes whenever it is convenient.A blinking check engine light means pull over, stop and call a tow truck.

Bobbo wrote:A solid check engine light means check the codes whenever it is convenient.A blinking check engine light means pull over, stop and call a tow truck.No, not even close.Blinking CEL is a DETECTED FAULT IN THE EMISSIONS SYSTEM, this MAY set a code but most of the time it will set a pending code if fault condition clears before the next cycle.If the fault clears before the cycle then blinking goes out and no code is set (there may or may not be a pending code),If fault persists into the next cycle then the CEL light is turned on (solid, no blinking) and the code is set..IF code has been set you have two different routes, a temporary code and a permanent code.Temporary code will clear it's self IF the fault no longer exists after 3 or more full ignition cycles (engine runs until it is fully warmed up then shut down and allowed to cool).Permanent CEL code will not clear without the use of a OBD reader.Just because you have a blinking CEL or full on CEL does not mean you must stop and have it towed.. It simply means there has been a emissions related fault detected and you should see about getting it serviced soon..Now, continual operation with a lit CEL could cause damage to the CATS or Oxy sensors PROVIDED you have a over lean or over rich fuel condition.. The best tool to own now days is a full on OBD reader (I am NOT talking about those Blue Tooth dongles)..A full dedicated code reader WILL not only read the codes but has built in dictionary of the codes it reads.. This makes troubleshooting much easier.Those BlueTooth dongles will often give you a code, but then you will have to do an Internet search to find out exactly what the code means.If you have a Harbor Freight store near you, they have multiple code readers.. They actually are a real good deal and work well.. With 20% coupon you can get the top of the line HF reader for about $112 and it reads engine codes plus ABS codes and the newest models also read the CANBUS communications codes as well..If money is a problem they do have more basic models starting at $49 but be aware some cheaper models can not remove codes and reset to CEL light. Best to read the manuals before buying (hint, HF does have the manuals online so you can read them before buying!)

Blinking check engine light | Good Sam Community

Campinfan
Explorer III
Aug 29, 2016
My F20 (2008 with the v-10) did the same thing. Turned out my catalytic converter went bad. Good news: covered by warranty. The Ford dealer asked me the color of the light, orange is not a "stop or you will destroy the vehicle", whereas a red light would be worse.
Gdetrailer
Explorer III
Aug 30, 2016
Bobbo wrote:
Gdetrailer wrote:
Bobbo wrote:
A solid check engine light means check the codes whenever it is convenient.

A blinking check engine light means pull over, stop and call a tow truck.

No, not even close.

2008 Chrysler Town & Country Manual wrote:
19. Malfunction Indicator Light
This light is part of an onboard diagnostic system
called OBD that monitors engine and automatic
transmission control systems. The light will illuminate
when the key is in the ON position before engine
start. If the bulb does not come on when turning the key
from OFF to ON, have the condition checked promptly.
Certain conditions such as a loose or missing gas cap,
poor fuel quality, etc. may illuminate the light after
engine start. The vehicle should be serviced if the light
stays on through several of your typical driving cycles. In
most situations the vehicle will drive normally and will
not require towing.
If the Malfunction Indicator Light flashes when the
engine is running, serious conditions may exist that
could lead to immediate loss of power or severe catalytic
converter damage. The vehicle should be serviced as
soon as possible if this occurs.

emphasis added

LISTEN UP FOLKS.

THE OP'S VEHICLE IS NOT A CHRYSLER.

Chryslers and Fords CEL lights OPERATIONS MEAN DIFFERENT THINGS, PERIOD.

Ford calls it SERVICE ENGINE SOON LIGHT.

DIRECTLY FROM FORDS OWNERS MANUAL HERE one page 13 of the Ford owners manual it says..

"Service engine soon:

The Service engine soon indicator light illuminates when the ignition is first turned to the RUN position to check the bulb.

Solid illumination after the engine is started indicates the On Board Diagnostics System (OBD-II) has detected a malfunction.

Refer to On board diagnostics (OBD-II)in the Maintenance and Specifications chapter.

If the light is blinking, engine misfire is occurring which could damage your catalytic converter.

Drive in a moderate fashion (avoid heavy acceleration and deceleration) and have your vehicle serviced immediately"

The indicator light in question looks like THIS..

It is only ONE COLOR and only has TWO "modes".. Solid ON and BLINKING.

Folks, please quit "comparing" other manufacturers CEL light functions to how Fords CEL light functions..

INSTEAD QUIT "ASSUMING" AND READ FORDS MANUAL BEFORE SPEWING A BUNCH OF WRONG INFORMATION....

The OPs vehicle is not going to self destruct with a CEL light blinking or on.

On edit..

stew47.. I would highly recommend you go to FORD TRUCKS ENTHUSIASTS FORUM

You will find nothing but FORD OWNERS WHO ARE MORE THAN HAPPY TO HELP OTHER FORD OWNERS instead of someone who "knows a owner of a Detroit Diesel" or a Chysler owner or a GM owner or a Toyota owner just making guesses at what a simple indicator light means for YOUR vehicle..

I AM a Ford owner of not one but THREE trucks with 5.4s, a 2003, 2006 and a 2013.. I can honestly tell you that this entire thread is filled with a lot of misinformation and it didn't come from me..
stew47
Explorer
Sep 12, 2016
Gde trailer thanks for all your help. Just an update then I'm going to that ford enthusiast page. I got truck in to shop and they scanned, only saw the po300, checked plugs and found to be in good shape. Found nearly plugged fuel filter so replaced. Lol accelerates again. All was well for couple weeks and when passing a car today the light blinked a few times and didn't stay on. I'm gonna check for code with my neat new blue tooth scanner. Thanks again all.
Gdetrailer
Explorer III
Sep 12, 2016
stew47 wrote:
Gde trailer thanks for all your help. Just an update then I'm going to that ford enthusiast page. I got truck in to shop and they scanned, only saw the po300, checked plugs and found to be in good shape. Found nearly plugged fuel filter so replaced. Lol accelerates again. All was well for couple weeks and when passing a car today the light blinked a few times and didn't stay on. I'm gonna check for code with my neat new blue tooth scanner. Thanks again all.

Good catch on the filter but obviously not the cause for the blinking light..

Most likely you will get another P0300 random misfire code..

Hopefully you will get another P03xx code which will help pinpoint which bank..

If your BT scanner is able to read deeper you need to check the fuel trim values and the Oxy sensors.. Weak Oxy sensors tend to switch on/off very slowly.

If Oxy sensors are not acting fast enough it can cause a lean fuel mixture under heavy acceleration.. That can lead to random misfire with or without an additional P03xx code..

Code reader should be a help but it may take time to catch it.
westend
Explorer
Sep 12, 2016
When I had a similar 0300 code appear, I waited a few days and the OBD code eventually listed the individual cylinder where the misfire was located. Since I knew all plugs were of the same vintage and firing correctly, I extrapolated that wiring or coil had failed. Wire looked OK so I replaced that cylinder's COP. I haven't had a misfire since. This is a Ford modular 5.4. Failure was at about 165K miles.
stew47
Explorer
Sep 12, 2016
Thanks guys. Yea I'll take my time to narrow things down a bit. I'll replace a cop or an 02 sensor if can narrow it to that.
Lol reason I can't just throw parts into it....
Since I bought in May.....
This issue
Tranny hesitates going into reverse when warm
New front drivers wheel bearing
New belt
U joints
Balance tires
Backer plates and ebrake parts.
I think I have 1200$ in it since May. I wouldn't call it a lemon yet I just want to NOT put any more money in it for few months lol.
dclark1946
Explorer
Sep 13, 2016
stew47 wrote:
Gde trailer thanks for all your help. Just an update then I'm going to that ford enthusiast page. I got truck in to shop and they scanned, only saw the po300, checked plugs and found to be in good shape. Found nearly plugged fuel filter so replaced. Lol accelerates again. All was well for couple weeks and when passing a car today the light blinked a few times and didn't stay on. I'm gonna check for code with my neat new blue tooth scanner. Thanks again all.

What APP are you using with your ELM 327 type OBD2 adapter? I have had good luck with the Torque APP for Android. The APP has explanations for the codes as well as links for troubleshooting the specific code if you have Internet connection. I can also monitor and graph much of the available realtime parametric data such as trim,O2 sensor voltage etc.
Denny___Jami
Explorer
Sep 13, 2016
stew47 wrote:
Thanks guys. Yea I'll take my time to narrow things down a bit. I'll replace a cop or an 02 sensor if can narrow it to that.
Lol reason I can't just throw parts into it....
Since I bought in May.....
This issue
Tranny hesitates going into reverse when warm
New front drivers wheel bearing
New belt
U joints
Balance tires
Backer plates and ebrake parts.
I think I have 1200$ in it since May. I wouldn't call it a lemon yet I just want to NOT put any more money in it for few months lol.

You bought a high mileage truck so some things will have to be replaced. Last year I bought a 03 F150 to save putting miles on my DRW, I changed all the fluids, belt and idler pulleys, front rotors and pads all around , idler arm, rotated tires, new battery and a few other things to make sure it was relable truck, it's all part of buying used.

Denny
DownTheAvenue
Explorer
Sep 13, 2016
wa8yxm wrote:

Happened to my brother once as he was pulling off the freeway in his Detroit Diesel Powered Semi. His made it to the end of the ramp and coasted onto the shoulder.. Buddy said "Wooee, Looks like the clown car at the circus with flames shooting out from under the hood"

He left the terminal with a Detroit Diesel under the hood. By the time he stopped (near instant after the light came on) He had two halves of a Detroit Diesel under the hood.. Not so little brother (6'6.5" tall to my 6'3" but younger) is a certified Diesel Mechanic (Also Auto) Inspected it, Hitched a ride to the truck stop a short distance away..Called Detroit D His buddy dropped his trailer and they went back intending to pull his tractor out from under his trailer, then pick up his trailer and tow it to the truck stop.. Tow truck was already hooking up to tractor (Detroit D sent the Tow) so they took the trailer back.. Detroit had a new engine, AND an installer, on a plane the next day putting it in and he was on the road again.

What, exactly, has this got to do with the original post and the problem it indicated?
stew47
Explorer
Sep 13, 2016
DownTheAvenue wrote:
wa8yxm wrote:

Happened to my brother once as he was pulling off the freeway in his Detroit Diesel Powered Semi. His made it to the end of the ramp and coasted onto the shoulder.. Buddy said "Wooee, Looks like the clown car at the circus with flames shooting out from under the hood"

He left the terminal with a Detroit Diesel under the hood. By the time he stopped (near instant after the light came on) He had two halves of a Detroit Diesel under the hood.. Not so little brother (6'6.5" tall to my 6'3" but younger) is a certified Diesel Mechanic (Also Auto) Inspected it, Hitched a ride to the truck stop a short distance away..Called Detroit D His buddy dropped his trailer and they went back intending to pull his tractor out from under his trailer, then pick up his trailer and tow it to the truck stop.. Tow truck was already hooking up to tractor (Detroit D sent the Tow) so they took the trailer back.. Detroit had a new engine, AND an installer, on a plane the next day putting it in and he was on the road again.

What, exactly, has this got to do with the original post and the problem it indicated?

I don't know but it's a great story!