Ok, let me try to reword. It seems if I turn ignition on for a second without fully turning the key on, it continues to try to start until it just stops. It sometimes just keeps on trying to turn over without me holding key all the way until it just shuts off. Don't know how to explain any better. Then sometimes it just gives a bogg, then shuts off. Sorry again for my description.
That behavior is somewhat normal. The 4th gen 4runner has an "automatic" starting mode. As soon as you turn the key to engage the starter, the computer takes over and keeps the starter engaged until either the engine starts, or until it times out after about 5 seconds. This happens even if you let go of the key.
Earlier 4runners (my '94) have an interlock where, after the engine starts, if there is not continuous airflow past the air flow sensor, the fuel pump will immediately shut down and the engine will die. This is to prevent fires in case of an accident that kills the engine but leaves the key on. You don't want the fuel pump to continue to run under those circumstances. An air intake hose coming apart can give you these symptoms on the '94.
I assume the 4th gen has a similar system, although it may be implemented differently. In your case, it's possible the ECU doesn't detect the engine has started, and shuts down the fuel pump as soon as you let go of the key.
Since this problem started
after you had the codes read, you really don't know whether there is a new code pertaining to this issue. You need to have it scanned again. Honestly, simple OBDII readers cost less than $20 - everyone who does any of their own maintenance needs to own one.
If there are no codes, you may have to take it to a dealer to have them scan it with a Toyota specific diag tool. That will provide them much more info than a simple OBDII scan, and will probably point to the problem.
A final possibility is a malfunction in the anti-theft ECU, although that usually results in no firing at all, not a brief start and then dying. Does your security system light come on in the instrument cluster? You might try starting it with a different key if you have one.
