Brit50

Have checked other posts but none exactly the same. Travelling along and engine will just cut off. Lights stay on everywhere. Put into neutral, turn key and engine fires back up. No rhyme or reason as to when or why this will happen.. Sometimes can travel 10 miles other times 30.
Went to OReillys and got these codes.
p0402, p0446, p1300

Anyone have any ideas where to start?
Do dealers have better software that can pinpoint better?

Thanks in advance.

ES300NZ

p1300 is http://engine-codes.com/p1300_toyota.html

ignitor or coil issue. I bet that's causing the cut out, the other two are minor, but need resolving.

808mcv20l

does this happen when going uphill?

The reason I asked is misfiring, lack of power when going uphill can be a sign of a clogged CAT.

you can test your coils, run the car and unplug each coil one at a time to see if there is a noticeable drop in stability and starts to run rough.

if there is no noticeable difference when unplugging coils that means that particular coil isn't working as well as it should. There "should" be an obvious roughness when the coil is unplugged.

How many miles does the car have? When was the last time the spark plugs were serviced?

I always fall back to the basics when troubleshoot performance issues, esp with a ton of miles and no obvious sign of where the issue could be.

Again the basics are:
Air, Fuel, Spark.

check air filter, clean MAF sensor, throttle body, iacv.
fuel injectors you can do the NOID light test.
spark, check for spark or replace plugs if they got a ton of miles on them. wires, coils check those.

Brit50

Engine runs so smooth that I can't see it being ignition coil. Have experienced IC before on another vehicle. I don't drive the car as much as I should. I used the car for 1st time in a month and went about 10 miles and no problems. No rhyme or reason. Maybe the car needs to get hotter.
No hills in Texas...haha
Thanks for the site with info on codes. I'll investigate further.
There was someone there who came across a bad wire to ECM. It may well be something like this.
Anyway thanks again for help. I know more today than yesterday thanks to you both.

Oro

These will certainly still be smooth minus one coil. Did the other vehicle you talk about have coil over plug design? That makes for very different symptoms.

Another thing is plugs. A cracked/bad plug will act fine sometimes until hot, then create enough resistance to fault the ign. circuit. Unfortunately, they can test fine on the bench and only do this under load and hot.

Not knowing the exact car, mileage, service history (these are good things to put in a post asking for help), there's a wide open field of guesses here.

Mrv8q

'91 Audi V8/5 speed
Oro, I'm impressed! Sold my Lago Blue 90 V8Q 12 years ago for my '99 ES300. Still miss the V8Q, but the Lexus is so reliable, it's allowed mr to experiment with old British sports cars. I can't imagine many V8Qs still around...

ES300NZ

well, the codes give you a place to look, sometimes these things really are what the codes say, and you'll waste alot of time look around the actual issue. Other times, .. it's like another member said, .. something nearby.

Brit50

Apologies taking so long to thank everyone. I really appreciate all the help and it gives me many things to try. When I find the answer I'll let everyone know. It may be a while simply because it isn't used much at the moment and we really only need the other vehicle.

mmatheny

"These will certainly still be smooth minus one coil." Wrong! My car has an intermittently bad #5 coil, and when it quits firing, the car feels like it is driving over a washboard! I was surprised that one cylinder not firing would make it run so rough!