Blinking CEL under load today?

[FdcCal]

So I head out today and encounter a problem I have never seen before. First I notice that there seems to a "shaking" sensation going up hill... Hmm, maybe it's the road. The guy with me notices it too, and comments. A littler farther on, the freeway goes up a fairly steep hill, well the rig seems to be working harder than usual, trans kicks down sooner, having a little trouble keeping up with the 60 mph traffic, more Hmm, something seems wrong, when I notice that the CEL is blinking, not steady on, blinking, and there seems to be a subtle vibration, maybe a load miss. After we crest the hill and start down, the CEL goes off. On the way back, same thing, blinking CEL under hill load at freeway speeds.
When I get home I scan the ECU, and no codes, none.
I keep this rig very well maintained, doesn't need anything tuneup or otherwise, all current.
2001 4Runner

Any ideas?

Thanks, FDC

 

[cougar428]

If I'm not mistaken, a flashing cel means that the engine is misfiring. Maybe one of your coil packs is going bad?

 

[Baja Runner]

Sounds also like could be a faulting knock sensor

 

[PitbullRescuer]

That's with out a doubt a misfire. A blinking CEL if for a misfire. Easy to diagnose. It's either spark, fuel or compression. So...

Scan it, see which cylinder is misfiring.

1.) pull the plugs and wires out
2.) compression test the motor
3.) if compression is good, change plugs and wires. Also move the coil packs around.
4.) if still missing, rescan it for codes. If the code moved to a different cylinder, it's a bad coil pack. If it didn't probably a bad injector.


You can also try changing your fuel filter at the same time but my money is on either plugs and wires or an injector.

 

[wareagle98]

Had the exact problem about a month ago, new plugs, wires, fuel filter, throttle body cleaning, and a new coil pack took care of it. runs great now...

 

[owenskp]

I have been trying to solve this problem for over a year. It still plagues me when I push my 4Runner over 75 mph. Pull over, turn it off for 30 seconds, continue down the road.
I know its a misfire, but I have replaced all coilpacks, plugs, wires, o2 sensor and cat. It still starts flashing at 75 mph. Could it be the plugs I'm using? NGK iridiums.

 

[BlackCat914]

that's the easy way to start fouling catalytic converters if you keep doing that.