When key is put into the ignition it will not turn to start. It seems the tumblers are not letting the key to turn.

you damaged the ignition switch and it will not recognize key you have to replace the tumbler and ignition switch the key acts like an electronic switch in most modern vehicles put key in and its recolonized and will turn and start vehicle ---damage to key or tumbler sets off anti theft and you have no start ---in future dont try to hot wire or pop ignition when keys are lost (thats all hollywood) go to dealer with vin and proof of ownership and they can cut you a new key

If you are unable to insert the key it might be because the tumbler has been turned past the point of key release it happens a lot with worn ignition tumblers try turning the ignition tumbler forward as if to attempt to start it without the key then try to insert the key if that doesn't work try turning it the opposite direction when you get it inserted you need to replace the tumbler asap if anyone who entends on stealing your car the knowledge that you have reported is enough to raise eyebrows of anyone who has bad ententions! I hope that solves your problem?

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The reason that the key wouldn't turn must have come from a malfunction of the ignition switch or the connecting rod, rather than the just the tumbler. Since the dash lights & gauges work now, at least part of the ignition switch is working, but apparently not the part that's engaged when the switch is turned to the "start" position.
By replacing just the tumbler, the dealership tech would have jiggled the connecting rod just enough to reseat it (and fix the jam that was causing the key to fail to turn in the tumbler), but didn't fix the real problem, which seems to be a worn out ignition switch or worn connecting/actuating rod.

Here's your steering column anatomy - illustration courtesy Ford Motor Company.

Sound like ignition teeth are just worn out from use. The reason the worn out key works better is inside ignition has formed to it, only way to fix this completely, is replace ignition, before no key works. Let me know , thanks mike

mcthrichter, I hope you are refering to the key and tumbler assembly for the ignition, if so I can take you through the procedure for replacing it and if not then you will have to resubmit your question. The column will not have to be taken apart but you will have to remove the cover. There are three phillips head screws under the column. If you have tilt steering then tilt it all the way up for easier access. There are actually four holes and the fourth that does not have a screw is the one to be concerned with for removing the tumbler. After removing these screws remove the top cover only. Tilt the wheel all the way down for this. Put your key in the ignition and turn it to the run position. (Do not start the vehicle) Insert a long thin screw driver into the hole in the lower cover that did not have a screw and push up as you pull the tumbler straight out. Put the new tumbler in the same run postion, push the little button on the tumbler all the way in, and insert it into the column and turn the key to the off position and remove it. Replace the cover and screws. Now, here is the problem. Your keys have a chip in them that is read by the theft detterent system and allows the vehicle to start. The new key may not have a chip and if it does it is not programmed for your vehicle. The keys that once started your vehicle will not start it now as they will not fit the tumblers nor will the new one until it is programmed. If you purchased your new part from a Ford dealer then they probably already informed you of this possibly. If you purchased it from a parts store they probably didn't tell you this. The best, and probably cheapest, way around this is to take your new tumbler to a locksmith and have them reset the tumblers to accommodate your present keys. This way also avoids having one key for the ignition and one for the doors. Good luck with this.

You have solved your own problem. I have replace many of these units. It is much simpler to carry and extra key than to screw arround with the old lock assembly. Keys and tumblers ware out like everything else. Let me know if I can help[

Hello there :
if you have some w-d 40 spray or a good penetrating spray spray a good amount in there and let it sit than go back in about 10 minutes and do it again then try to use the key and wiggle it up and down as you are inserting it in there also a long sharp kitchen knife can help loosen the tumbler but if this all fails they you will have to have the tumbler either replaced or repaired ok?
best regards michael .

The end of the lock cylinder usually breaks off.

you need to buy a new ignition tumbler

Replace the ignition tumbler--i.e. get a new ignition set with new key. This will require removing the plastic trim around the steering column and removing the old ignition set. It's a good DIY project, but you should get a Haynes manual for 83-88 T-Bird/Cougar. Try going to a junk yard for the replacement part. Crown Vics, Cougars, Grand Marquis', Lincolns all have the same type of set for those years.