Randomly not starting

I recently had the alternator replaced in my 99 4Runner. They checked the battery and everything else is fine, however, sometimes it won't start. The lights come on but when I turn the key there is not a sound. I had it jumped both times it happened and it did start but it doesn't make sense if the battery is fine. Could it be the starter? Thanks in advance!

 

Doubtful. Starters and alternators rarely go bad on these.

Especially, if a jump starts it, the starter should be good.

You probably have a bad wiring connection between the battery and the starter. Check all the grounds to the engine and body and look at your battery cables and see what condition they are in. They can rot from the inside out.

Applying extra voltage from a jump, can reverse corrosion in the cables or a connection enough that it will start. It will probably start for a while until the corrosion comes back.

 

When do you experience the periodic not starting issue? Does it happen after a while where the vehicle has sat inoperative or can that happen at any moment? If the former, then I'd call it a battery issue. If the latter, then a bad connection.

 

check wiring...especially battery...