Driving home from work yesterday, coming off a traffic light and all of a sudden the CEL and skid light both start flashing, I lose most power and the truck seems to be shaking very violently- I grab the 4 wheel lever, which seemed to calm it down. I pulled into a auto parts shop in hopes to get a computer read-out, but the line was too long and I had an appointment, so I checked under the hood for anything unusual, seeing nothing I started the truck again and this time-it started right up and no warning lights. I drove home thru heavy traffic, no problems and drove to an appointment this morning, also no issue.
I did stop at an auto parts dealer, but they said if the warning light wasnt on the code reader would not identify anything. Should I take it into the dealer or are there other things I can check (oil is fine, coolant is fine, cant check the tranny because of the sealed nature of the thing)- any other recommendations?

Thanks

Hi tkeratt,

Judging from your description of the issue, it just seems like you had some 'fluky' software glitch that we all encounter (or will) from time to time. That said: just do an ECU software/firmware 'Master RESET' BEFORE you spend any of your hard earned currency taking it in and hoping the shop can locate and repair the problem(s). It's very simple to do and can be done while you're counting sheep lol!

The gen-5 4Runner has many ECU's (Electronic Control Units), nearing 25 to 30 in the main body compu network alone, all communicating via the canBUS system... That's not even including the PCM (Powertrain Control Modules) and it's Sophisticated software network. But all of these systems, no matter how intricate and self sufficient, are becoming increasingly vulnerable as their responsibility to work together and to synchronize are increased.

Just like your windows laptops, there are temporary files and history logs being stored in the hard drives, which do take up space (in the caches) and files do corrupt as they age. So I do like to advise that these temporary file folders be cleaned out from time to time. Because these ECU's are designed with the ability to store data even when the main battery is disconnected for the purpose of serviceability. So the service techs can disconnect the battery during routine maintenance tasks and not need to be concerned with the customer's radio presets or resetting the GPS's compass after having the battery's cables disconnected for an hour or two.

So... should you ever need to perform a master RESET, you'll need to disconnect the negative battery cable for a minimum time period of four hours. I'd recommend to disconnect the battery after the vehicle is back in the driveway for the night. This will help eliminate the inconvenience of anyone needing to use the truck but can't because a master reset is being performed during the day. The next day when you go to start it up, the truck will start up as always, but will shut-down after two or three seconds: Don't panic, this is perfectly normal.

Simply restart it again and it will run as it should. I suspect that this is a matter of all of the ECU's being recalibrated to their Factory specification and deleting all of the old, corrupt history log, temp files, and saving the changes. Anyway, this should work better than anything else that you could do to restore it's factory operation! I've done/recommended this technique more times than I can recall, but it's worked 95% of the time! Let us know how you make out, 'Best to you',

rig

You'd need a scantool that can pull history codes most likely if the light is staying off. I'd imagine that you'd have a few P030x DTCs since it was misfiring. Basically the MIL flashing means it's got a bad misfire and should be turned off when safe, but you probably didn't do any damage.

It could be a software glitch, it could be something intermittent. It's hard to say without at least either replicating the situation or pulling the vehicle's DTC's. I'd say if you're on a budget and don't want to deal with the dealer, try Rigtec's suggestion and if it comes back have it checked out.

You can also check the air intake system (vacuum hoses, maf sensor, loose connections). Also, just because the check engine light isn't on anymore doesn't mean the code isn't still stored in the system.. So you can still have them use a scan tool to see if its still there or not.

I would start looking over the wiring for signs of chaffing somewhere and especially rodent damage. Toyota (and a bunch of other mfg's) apparently use peanut butter flavored wiring that rodents love to chew on. It's happened to a few Toyotas in my neck of the woods, all with symptoms similar to yours.

It's soy flavored. :P

But wiring would be an issue, I recently had to replace a knock sensor sub-harness in a 2015 because a mouse decided to nest in the engine valley. Thankfully I managed to do it without pulling the engine out...

But yeah, the main issue is it's not happening now and the MIL is off at this time. So there's probably History DTCs stored, but you need a scantool that will read those (not all Generic OBDII tools do pending & history DTCS if I recall).

It's up to you, you can just drive it until it happens again if you don't have time/money to get it looked at now.

Thanks Rigtec (and thanks to everyone else here for your comments- have not tasted the wiring harness recently, but if I am ever that hungry I will let you know whether I got the peanut butter or soy flavored version!!!)

I will do the reset this evening and will let you know the results- have had no issues since this event on Thursday, so I am thinking it is a software glitch.

Again, thanks - now if anyone can figure out how to get my wife to stop blaming me for the heavy traffic and rainstorm we got caught in on the motorcycle yesterday- please let me know!!!!

Happy 4th to you all

Tkeratt!

Rig, worked like a champ, just as you described. Thanks so much and hope you enjoyed your 4th of July as much as we did here.

Again thanks
Tkeratt!