This is a problem that started a couple months ago, and I've taken it to two separate mechanics. Neither knows what the problem is. Basically, most times I try to start the car (~75% of the time), it cranks, and keeps cranking, but does not start. I have to pull the key back, and turn it again. Then it starts no problem. Not fuel related, as pushing the gas while it's cranking and not starting does nothing. It's not regular either; sometimes it starts first try on a cold start, sometimes not. Sometimes it starts first try after driving for a while, sometimes not. It's a 2004 with 130k miles.

Interestingly, I am pretty sure this started when I got a new key. The physical key shell snapped and separated from the blade. I ordered a new one, and put the old transponder into the new key shell. I haven't had any sort of anti-theft problems afterwards (unless this is one). Any ideas?

 

Try turning the key to the run position, waiting a moment while the fuel pump runs, then starting it.
Could be a weak lift pump in the tank.

Chip H.

 

Pushing the gas pedal down while trying to start does nothing on a fuel injected vehicle, with a TBW gas pedal. It's all computer controlled, it doesn't acknowledge your input until it's ready to, and it's not ready to while cranking over trying to start.

@chip9's suggestion above is a good one. I'd also ask when the last time the fuel filter was replaced, as it could be plugged and inhibiting the flow of fuel.

As for the key theory, I wouldn't think it would even crank if there was an issue with the key.

 

I've tried leaving the key in the run position for up to 20-30 seconds before starting, it still has the same symptoms. Fuel filter was replaced approximately 3k miles ago, and throttle bodies were cleaned.

 

Fuel pump will only run for 5-10 sec when you put the key to the run position but don't crank the engine, after that point the fuel pressure will start to drop if there's an issue with the pump. Try a shorter pause in the run position before cranking over to test this theory.

 

If it were the immobilizer not reading the RFID chip in the key, I would think the security light would still be lit/flashing on the dash.

http://drivers.lexus.com/t3Portal/do.../04gx41/11.pdf

crddfltswp - Make sure that light comes on when you first turn the key (during the warning light test) to make sure the bulb isn't burned out. If the bulb is good, and the light goes off once the test is complete, then the chip in the key is being read successfully, and the problem lies elsewhere.

If the light stays on, then the immobilizer isn't reading the chip. Remove the key from your keyring so that there's nothing to interfere and try starting it with only the key near the ignition cylinder.

Chip H.

 

The light does go on, and then off. So that appears to be good. After leaving the key in run position for 5-10 seconds before starting, the same symptoms continue.

 

Have you ever replaced the spark plugs? What's your fuel economy like?

In your 1st post you say it just keeps cranking but doesn't start, and you have to pull the key back and try again, if you didn't pull the key back would it just keep cranking, or does it time out after a while?

 

It just keeps cranking if I don't pull it back. I've let it go for quite a while (probably 20-30 seconds, again). I can let it go longer and see when it cuts out. As for fuel economy, it was pretty bad a few months ago. It threw a P0051 code, and I replaced the front passenger O2 sensor. Now it's back to normal, 15-18mpg or so. The same mechanic who replaced the O2 sensor and cleaned the throttle bodies checked the spark plugs trying to diagnose this problem, he said they looked fine to him. This was at a highly rated independent shop in Austin, TX. I've had good experiences with them.

I do think the exhaust smells a little rich after starting. I always chalked that up to having to crank it twice, and the fuel pump sending more through.

 

This thread might be relevant:

http://www.tundrasolutions.com/forum...-shaft-sensor/

Theirs threw codes though, and you didn't mention any other than the O2 sensor. The CKP sensor tells the computer when the engine is turning over, and when the RPMs are high enough, to release the starter.

Chip H.

 

Hi did you fix your issue ? What was the problem? I'm having the same, at morning it starts just well and during the day I have to try like 7 times then in starts and works just fine

 

It sounds like the check valve that retains fl pressure went bad.
I would say put the key in the run position, then off, then run, then off. Each time it’s in the run position... leave it there for 5 seconds.
Then start it... if this consistently works... it needs a fuel delivery unit(not just the silver pump you can replace, but the entire unit.