Is it the starter?
 

1999 4Runner - Recently I have been getting the 'click click' when trying to start. Doesn't happen all of the time, but when it does sometimes it'll start after a few tries. If that doesn't work I attach a battery pack and it'll always start. Replaced battery (costco), but it still happens.

Read all of the posts about replacing/troubleshooting starter and have new contacts. Before I pull the starter wondering if that is the issue since it'll always start when I attach battery pack.

Checked voltage and always around high 13/low 14 volts.

Thoughts?

starter if the volts are right-As the starter gets older it takes more power to--well--start. That could answer why it starts with a jumper.

Also check your cranking amps--

Id say its a yes on the starter..

When mine was on the way out it would take a few tries turning the keys..
I replaced the contacts and all is well

Props to you for searching though.

Welcome and good luck fixing it..

:dj:

x2 on replacing the starter contacts now. I had the same symptoms but put off fixing it because the problem wasn't too bad.... Like Buhundred said- One day the starter kept cranking and would not disengage from the flexplate. I made the mistake of trying to move the truck to get it to disengage and ended up cracking the flexplate.

-Scubaduck

I had the same issue with my tacoma. 99% sure it is the contacts. I replaced mine and she is fine again...here is my thread.. in the photos you can see the worn battery side

https://www.yotatech.com/forums/f2/p...-issue-184572/

I don't have a 4runner but I can imagine things are pretty close.

have a fire extinguisher handy and keep it in the truck so you will not need it.

Other members have had this happen leading to a fire.

Yes it does sound like it probably is the starter contacts however you have not mentioned the cables nor the ends of them. Are you sure they are corrosion free and well crimped at both ends? They sometimes pull out just a bit from the connector.

I am thinking when you attach the jump starter it initiates more pressure on the cable end thus making a solid connection. Total mileage on the vehicle is what please?

Starter