My wife's 15 IS350 is having an intermittent no start issue. Well to be honest it seems to do it every damn time I'm out of town.

First time was while back there was heavy terminal corrosion and I replaced it with a new terminal i picked up at AutoZone. Worked fine for a year +.

Then a few weeks ago it does it again, while I'm out of town and AAA put in a new battery and it fires right up.

A couple weeks go by and you guessed it I was out of town again and it does it again. AAA "cleans" the terminals, tests the battery and can't figure it out so they tow it home. When I got home I took the cables off the stud and cleaned that part (which they hadn't) and it fired right up. Ran fine for a coupe days so I ordered a new Toyota positive and replaced it. Made sure to clean all the terminal ends, etc. This was on Sunday. Tested a few times and its fine.

Today, no start again. I loosened the stud nut and retightened and bam, it starts again. WTF. Anyone have any ideas? Corrosion has been an issue so I'm thinking maybe the starter cable needs to be replaced. Anyone have any experience with that?

 

When you refer to the no start condition, I'm assuming you mean a "no crank no start" situation? Do you hear a click noise, or repeated clicking?
When it happens, can you turn on the headlights and play the radio?

The first mention of the heavy corrosion sounds like you needed a battery at that time, not just the terminal.
So if the battery lasted another year+ that is kinda bonus since it seemed to be sulfating already...and likely still during that year+.

 

Correct no crank no start. I can hear a single click, I assume from a relay, but nothing beyond that. The rest of the car power is fine, headlights, radio, etc.

Also I forgot to mention, I did replace the battery when I did the first terminal.

Another odd thing. Every time I disconnect the battery when i start it the first time the car will fire up then turn off. It runs fine after that until this no crank situation shows up again.

 

Another odd thing. Every time I disconnect the battery when i start it the first time the car will fire up then turn off. That's actually normal, first start it will stall right away and restarts just fine after.
A single click could be the starter...if battery voltage is low, say 9V, then you will normally get repeating clicking. But a single click usually points to a starter issue.
Keeping in mind I haven't heard the click myself, so it's possible it could be something else.
But if you get the single click, and then whatever you do makes it start, that means the battery wasn't dead, and if it did click then the connection to the battery should be good...so that means it's something else.
It would be nice to know where the click is coming from in the engine bay. Now that the weather is getting cooler, this is likely when starter issues will start to show themselves...not too often starters go when it's warm out.

 

Gad to hear the stall is normal, that takes one thing off the table.

The odd part is all i have to do to get it to fire is mess with the positive terminal and it'll start cranking like normal, which would be odd for a starter failure to be that intermittent and sensitive to the terminal. Regarding cool weather, I'm in Houston so its only just getting into the 70s here and its a garage queen

 

Can you see any obvious corrosion on the wire leaving the battery? Or is the cable swollen anywhere you can see?
Messing with the terminal may be just coincidental as to why it starts...just suggesting that as a possibility. Of course I'm not there with the vehicle.
But if you can get it to click consistently, then that might be your chance to find where the clicking is coming from.
If it leads you to the starter, then that narrows it to the battery, battery cable (including terminal), or the starter.

 

I'm going to check the battery and jack it up this afternoon. I'm hoping I can get it to do it again and chase the click. Any idea how hard the cable is to replace? I've seen the starter is a PITA and needs a manifold to come off.

 

OK I can't replicate the click only. It's starting fine now. I did jack it up and everything looks good from underneath, at least as much as you can see which is basically nothing.

I checked the wire going from the positive terminal to the starter. It definitely has some corrosion. Pics attached. I pulled the electrical tape off and pulled bac the loom. I did notice that the first inch or so of the wire is too stiff to bend. It will only start bending about an inch below the insulation. I'm thinking the corrosion has gone down the and isn't letting it flex. It doesn't look like this connection is soldered and that could be creating it, but I could be wrong. I'm thinking this cable needs to be replaced. Which will absolutely suck since it appears the starter might need to come out for it.

 

I'm not sure if the stiffness in the first inch (that's what she said ) is an issue...I'm gonna check my car next time i head out to see.
They probably vulcanize the end before crimping the terminal on so that contaminants can't get into the cable.
Some surface corrosion is fine and expected...I was more looking for a giant green hot mess.
The cable diameter in the first inch also looks consistent to the rest...so if it was corroding I would expect it to be larger than the uncorroded cable.

 

^^ LMAO - OMG that made me laugh!! Not only are you a wealth of knowledge and so helpful, you actually have a wicked sense of humor

 

LOL walked right into that one.

So, the first time I ever addressed this, back when I did the first battery, it was a massive green blob. It's been cleaned 4-5 times since then and as recently as last week, so it could be worse inside there than I can see.

I ended up ordering a new cable and I'm going to see if I can swap it without pulling the starter. I have a feeling it's a fools errand but I'm a glutton for punishment.