First off i'm tryng to prevent just ripping out expensive $$$$$ parts and replacing them.

My truck 91 4runner 3.0 wont start somtimes i tested everything out alt patern good starter draw good battery low charge (somtimes). I'm thinking i may have a unusual parasitic load...(which is why i havent swapped for a new batt) i'm planning on testing that when i get some spare daylight!! I'm having a constant battle with corrosion on the batt itself even with using anti corrosion spray.... So that leads me to possible wire corrosion (internal)

thanks for your thaughts!

 

my 4Runner had a random no start too but i tested the ignition coil and it was dead soo i replaced it if you haven't checked that i would..good luck

 

i say check your cables. does your engine has a starter relay? if so check that too

 

I have had a simular problem. I replaced the neg batt cable and that has fixed it for now. I have a new pos cable that I need to install, just looking for time. However right after I swaped it out the truck broke hard. So I havent had a lot of starts to make sure this was the fix. You may want to try the red and green felts that go on your batt post. They work great at preventing corrision. Good luck Bryan

 

I'd check for codes. Actually, I'd reset codes and wait for it to happen again. Make sure code is zeroed, then drive it. Next time no start, check code right away. The ECM might try to help and let you know what's wrong.

My vehicle has a similiar problem, and throws a code 12 when it won't start. I think I have a problem with the distributor circuit. Might be as simple as a bad plug, but I am still working on solving it.

This method might help you find your issue. Intermittent problems can be a huge headache. They are for me at least.

 

Similar thing happened to me on my 92' 3.0. When I would start it I could tell the starter was working, but not quite the way it should. Sometimes it started fine, other times I would crank it off and on for a good five minutes to get it to go. I first started by cleaning the post terminals every week, did nothing. Second, I changed the negative battery cable, which fixed it for a bit but then the problem returned. What I finally had to do was replace the contacts inside the starter, two little "L" shaped copper deals. About half the involved part was worn down. I forget what I paid for them, but it wasn't more than five bucks and an hour of work, and it fixed the problem.