I have a 2005 Ranger with a 4.0 (4x4) and an automatic transmission. It has 93K on the clock. Yesterday I was driving up a long grade when the engine bucked just once. The CEL flashed a few times but stopped before I could count the flashes. The light did not stay on. I was going about 48 MPH and just under 2K on the tachometer at the time. It was in overdrive at the time but already to shift down. When I got home I connected my code reader but it showed no codes stored. It ran a little rough under the same circumstances last fall but I did not have the CEL flash. I changed the plug wires dumped in a can of Sea Foam and it hasn't done it since, until yesterday. I'm going to dump another can of Sea Foam in it today. (The plug wires are lifetime warranty parts) My brothers F-250 with the 5.4 has done the same thing (his has 8 individual coils). Any ideas????

 

Flashing CEL with the engine is running means severe misfire. The flashing of this light is to warn the driver that the misfire is severe and that prolonged and continued operation of the vehicle with the condition can damage the cats. However, it's not exactly clear from the OP if this is what is happening. Also, there is no information embedded or related to the number of times the CEL flashes and any specific problem.

 

I now know what the flashing light means but it doesn't help me with what the cause was. The CEL on my old 98 Ranger flashed on one occasion. It flashed a series of 5 flashes for 3 repetitions and then the light stayed on steady. I was able to retrieve a code of cylinder #5 miss fire, which ended up being a bad fuel injector. In this case, the light didn't stay on and there are no codes stored. The spark plugs and wires are all new last fall (about 6K miles). The truck is running like a champ again after I added a can of Sea Foam to a full tank of gas.

 

take it to an autozone, advanced, or similar and have them run the stored codes

 

All I have is a code reader which picked up no codes so I took it to the repair shop that I go to. They have an elaborate scan tool and it picked up no stored codes either. I guess that I will have to run it until it gets bad enough to produce a code. It's running great right now.

 

mine would buck up when going up a hill (but no CEL flashing). Found out that the spark plugs were gapped too wide and when I re-gapped them, the bucking went away.