2003 Toyota Tacoma won't start when it's hot?

I have a 2003 Toyota Tacoma pickup.

I bought it used in the spring of 2009. I drove it for a few months without any problems and one day this problem developed. It won’t start on the first attempt. Or it will start and then immediately die. It will take two or three tries to get it running.

I took it in to my mechanic and he couldn’t find anything wrong. I got a tune-up anyway and it drove like a champ. Until the next day when the problem came back.

This persisted for a few weeks more and then went away.

This last summer it started happening again and continued up through October and went away again.

I think the problem seems to happen when it’s hot in the summer.

Any ideas?

Thanks!

Do you know whether your mechanic read a code off the diagnostics port?
When you first turn the key right before the position where you start it, do you hear a slight ‘whirr’ sound for a couple of seconds?
If you shut it off, leave it briefly for -say- a couple of minutes, does it start right back up?

RemcoW’s leaning towards the fuel pump, so listen for that for a while, both when it starts and when it doesn’t. That way you can tell the difference. It’s installed in your fuel tank. Check it out, it’s a good start.

The next time it won’t start hold the pedal to the floor and turn the key. Then ease up gradually on the pedal is this gets it to fire. If that works then check the vacuum line for the fuel pressure regulator & replace the regulator if you find any fuel in the line. If that looks good then ask a shop to check for leaking fuel injectors.

I have a '96 Tacoma. The systems have to be different but I experienced the same problem. I found an obscure forum with a solution to mine. I simply unplugged the temperature sensor on the air filter box. Go figure. The check engine light stays on, but it starts every time in the heat. The temperature sensor works but he ECU doesn’t understand it. At least that’s the way I figure it. I hope your solution may be just as simple-and cheap.

I would guess your fuel pressure regulator is leaking into the vacuum hose and into your intake.

It sounds temp related to me…High temp that is… I am thinking that your coil pack may be on its way out…when a coil gets hot they can leak voltage from the coil pack body to ground. Now I am not saying this is your actual issue, but it sure sounds familiar. DO you have a coil pack or is this engine a coil over plug with individual coils over each plug…it matters. At any rate…this high temp issue can do the same thing to most electrical sensors and coils…if they have a tiny breech that breech is were current will go when hot.

If it is not what I am thinking another thing you can try that involves little to no work is a nice fuel injector cleaner in your tank. I find that Chevron Techron works rather well…its worth a shot just to see what happens. Techron is sold in tiers…there’s a cheapie…and an expensive one…I usually buy the one down from the most expensive and add it to say a half tank to concentrate the mixture a bit… Worth a try. You r fuel pressure regulator could also be leaking pressure when it gets hot and sits a while…thats another item on your symptom checklist also… I would check and clean the MAF too…

SO…see if you have a coil pack or coil over plug. Go out at night and open your hood and in the dark see if you see any fireworks near the coil pack and or wires…but I strongly feel this is coil over plug and in that case it wont work. I wanted to see if you can see any voltage leaking at night in the dark…

Sorry for being all over the place with a solution, but this issue can have MANY causes… From spark to fuel…

Blackbird