my check engine light is blinking and the engine is skipping bad.i have a very big loss in power ang gas milage also.
97 f-150 flareside 4x4 4.6 automatic. 103,000mi. i need help bad.

 

A blinking Check engine light is a misfire.

Change your plugs and wires.

For now, reach in the engine and push your spark plug wires down into the engine. One will probably push in a little. Don't bother trying to fix it and re-install. It won't last. The engine will warm up and start skipping again.

I bought NAPA Belden wires with a lifetime warranty for $64. It seems because of the design of the boots/engine the heat eventually gets to them, and the wires pop themselves of the plug. I know they will too eventually fail so i bought ones with a lifetime warranty.

BTW, it ain't easy. You need a sparkplug socket to hold the plug while installing/removing. An array of 3/8 extentions and swivels will be handy, and a small screwdriver or pick to pop the wire looms. IMO the wires were harder than the plugs.

Di-electric greese. Get a big tube. And while your at it, greese up your fuel injector plugs, you'll need to unplug them for access to the spark plugs.

Someone on this site mentioned unbolting the wiring junction block on the passenger side for better access. I did'nt, but i guess it only takes a few bolts, and makes it much easier.

Unhook your battery for safety and for check engine light reset.

Good luck

 

I wouldn't drive it while it's blinking. Also, plan on replacing your catalytic convertor. Engine misfire will set the check engine light. Rapid continuous misfires will cause the light to blink and if it's blinking it means that it's dumping enough unburned fuel into the exhaust that it's going to kill the cat.

-Jon

 

My truck started doing this exact thing this morning.

I had my wires and plugs replaced just 1,000 miles ago at 40,000 miles because the wires were bad and I had my mechanic replace the plugs too (platinum plugs, upgraded wires). This morning the truck was running strange when I was accelerating (hesitating, running rough, almost felt out of balance) but once up to speed it was fine. Then the check engine light came on. When the wires were bad before it was acting similar (rough idle, engine was running rough under acceleration) but the check engine light did not come on.

I will go check the connections and reset my computer.

 

same song old dance: time to look at the forgotten step children of your emission system,the oxygen sensors,they will and do go bad.65000 is the recommended replacement window. now heres the real kicker, the front two run around 65 each the back 85! honey i wont be home tonight! and you cant just replace one its all or nothing. seems the computer reads the front two adds them together and verifies its math at the back one. if the computer gets a f in math on comes the red light and the computer goes into open loop and gives you enough to get to the shop....a new age and i remember installing my spare points in the middle of illinios with a beer tab i found on the edge of the road as a feeler gauge, on my 69 chevelle

 

Last night I went out and checked all of the connections between the wires and coils and wires and plugs. Then I re-set the computer. I drove it around the block and the check engine light was gone but it still ran rough. This morning it ran rough at the start but after a couple of miles it ran like new. I will drive it around at lunch and see how she acts. I have a feeling it was just a loose wire and re-setting the computer after fixing the loose one did the trick. I guess it just takes a few miles for the computer to go back to normal.

If it starts running rough again I am driving it straight to my mechanic.

 

Tex, the o2 sensor won't effect how the truck runs, just the gas milage and emissions.

-Jon

 

i changed the plugs and it helped a lot. it still has a slight misfire im gonna do the wires tommorow.

 

Blueflareside,

I had a similar problem with my '97 4.6L. I had the plugs and wires rplaced due to a misfire. It worked for a few months and then started back up again. Upon pulling the plug that was showing a misfire we found carbon tracks down the side of the plug and a rusty plug. Replaced with a new plug. Worked good for a week and then the same problem, but two plugs this time. Same deal...rusty plugs and carbon tracks.

New wires and plugs again. They worked good for a few months and then the same problems...rusty plugs and carbon tracking.

New plugs again and FORD spark plug wires (not cheap), but considering that it has solved the problem for over a year now I guess the extra cost was work it.

The after market plug wires just don't seem to seal around the top like the Ford wires do.

Moral of the story. Ford wires seem to be the best.

 

medic,

Thanks for the information. I am taking it in to my mechanic this morning and will tell him about your post.

 

i thought i had it fixed it was running good for a day but it started acting up again.same symptoms blinking light and a misfire.im thinking its time to trade it in.

 

Bill, did you put the new wires in yet?

 

i changed the wires. and still the same problem.

i went and looked at a 2002 f-350 super duty today.leather interior,fully loaded.diesel,and a manual tranny. but im still undecided if i wanna get a new one.

 

If you have a flashing check engine light you need to stop driving the truck. You have a serious problem I'm not going to tell you what it is but your cat will be destroyed among other things. When you reset the computer you just lost all information of diaging the problem I do this for a living , the light hasn't come back because it has to cycle so many times before it will. Have it checked out soon as possible. dan

 

Hi this happened to our 98 f150. We changed the coil out and put b12 in it. Seemed to run fine. Now ENGINE light flashing flashing and acts wierd. What NOW? It has over 220,000 miles.