I have a 2004 Tundra that starts 90% of the time, but will not start on occasion.

I have taken into my mechanic as well as the dealer and they can't reproduce the issue. Sometimes it starts and sometimes it doesn't. Have to turn through ignition repeatedly and it will finally start and work great for weeks, then it's same old story. Replaced neutral safety switch and ignition switch. Ideas?

 

When you say not starting, I assume you mean it does not crank, correct? Perhaps the starter - next time this happens, check the voltage on the battery as you are trying to start it. If the voltage is dropping when you turn the key, the starter is getting juice but not turning. If that is happening, replace the starter. If the voltage is not dropping, it is upstream of the starter.

 

Starter solenoid?
You can rebuild it for $30 ish.
Aftermarket starters haven’t been any good to me.
Rebuilt oem and works great. Returned the aftermarket.

 

Your issue could be caused by just about anything. On our aging Lexus it was the burned up contacts in the starter solenoid.
The Toyota starters are typically quite durable but the contacts, not so much.
Easy to remove a starter on a V-6 Lexus ~ on a Tundra V8 it's a different story.

Good luck and keep us posted with your results.

Chuck55

 

It just clicks. Same behavior when the battery is dead. But after repeatedly turning the ignition it will start and work for weeks, then starts all over again!

 

I had similar issues with a 1990 4Runner. Completely random start/no start. I replaced the starter, starter relay, ignition switch, neutral switch. The only thing that worked was bypassing the starter relay. After doing that had no issues at all

 

Then 100% chance it is a worn starter contact, get the correct kit and get er' fixed.

Oh and if you don't and decide to delay, it will get worse, your current 90% will steadily drop to 0%. Just an fyi, luck.