So I can start my 4Runner, but once I let my foot off the pedal dies and in the process the 15a efi fuse burns up. What's causing this and how can I fix it?

 

Electric is not my strongest point, but I would check the O2 sensor and make sure it has gotten he wire up against the exhaust and melted a wire.

Check your Main EFI Relay and reseat and check the cable to your Air Flow meter, look for knicks and cuts.

There are several other circuits on that fuse but I just looked at the most easiest to check. Other then that you will just have to break out a meter and pick one circuit at a time and see if all is well. There are others far better in this area then me that might have some better ideas, I just go for the easiest first.

 

You didn't say which pedal, or the motor and transmission type.

Does it stay running if you do not release the pedal?
Can you turn the key to on without depressing any pedals and the fuse doesn't blow?

Terry gave you a good start with the oxygen sensor, they also get damaged farther up the wire some times and ground out to the transmission or the body, aswell they maybe internally damaged.

If you mean the throttle, there isn't alot of choices the air flow meter and the throttle position sensors are the only two that come to mind.

I don't think any of the clutch switches are connected to the EFI fuse, but I can't look at the wiring diagrams currently. You could inspect or disconnect the "start clutch cancel switch" on the dash if you have one, but again not sure it's even on that portion of the circuit.

 

P.S. Make sure you have the correct sized fuse in for the EFI (Knew there was something I was forgeting!)

 

Someone bumped a thread you might find usefull. Link

The short version is to unplug the connector to the gas tank and use a meter to check for shorts to ground.