call a lock smith .
You can't repair it you can only replace it.
Replace the ignition. That would involve tearing down the column a little bit. A very common thing seen by a locksmith.
One to repair an ignition switch on your Astro Van is buy a replacement steering column from a local salvage yard including the ignition key, and replace the whole steering column. RC Houston, TX
Remove and replace it.
I recommend you getting a repair manual at your local automotive store.
You cannot repair a blown head gasket, you must remove the heads and replace the gasket.
fairly simple to remove and replace. most shops can remove in 30 min or less.
I'll include a link to a video below that will show you how to repair the ignition coil in your Ford F250 or F350. hope this helps.
Here are some notes I found on: http://experts.about.com/q/Toyota-Repair-832/91-tercel-steering-wheel.htm The ignition lock cylinder needs to be replaced, the only way the cylinder will come out is if you can get into the "acc" position, there is a release pin on the housing that you have to push in to remove the cylinder,. remove the covering around the locj to gain access to the pin, it may be a good idea to buy the new lock cylinder first so you can see where the release pin is, if you can not get the key into the ACC position the lock cylinder needs to be drilled out and I recommend having a Toyota dealer or locksmith deal with this.
Remove and bring to radiator repair shop or replace at 1-800Radiator
You cannot repair a blown head gasket, you must remove the heads and replace the gasket.
replace cam position sensor