2nd generation Tacoma long cranks

Hi, I have s 2006 Tacoma 2.7 and have starting issues. I always have to crank the engine twice before it turns on. If I run the engine for a while then turn the engine off for 5-10 min and try to start it up angain, it will start up immediately. I took it in to Toyota twice and they couldn'tfind out what the problem was. My guess is the crank position senor but I am unsure where it's located. Please help! Thank you.

 

I've always felt my V6 is also slow to start - compared to all our other Toyota products, it takes the longest to start. I have a 2nd battery and when I engage both batteries to start the truck, it turns over faster and starts sooner. I don't know if that's affected by the position sensor; I've never diagnosed it. However, the engine has never failed to start and I still have the original starter.