MY 1994 FIREBIRD NEEDS ITS FREEZE PLUG REPLACED.HOW IS IT DONE.

Yes. There are two or three freeze plugs on the back of the engine, under the bell housing of the transmission. The suggestion to use a rubber expandable freeze plug may work, depending on which one(s) are leaking, but that is a temporary fix. And I'm not sure you can get to the top plug with the flex plate and torque converter in place. To do it right, you need to remove the transmission and put in a standard all-metal freeze plug.

That really depends upon which freeze plug needs replaced. Some are easy to get at and can be done in minutes. Others can be so difficult they may actually require engine removal to get to.

DEPENSING ON THE ENGINE, THERE MAY BE A FREEZE PLUG BEHIND THE PAOWE STEERING. ALSO A POSSIBLE HEAD GASKET PROBLEM OR BAD INTAKE MANIFOLD GASKET IS IT IS A V6.

freeze plug

It would need to be flashed. This can be done before it is installed in the car. You'll need the VIN number, year, make, model, and engine size.
http://www.autozone.com/autozone/parts/1994-Pontiac-Firebird/Engine-Control-Computer/_/N-j164mZ9gsp8?filterByKeyWord=computer&fromString=search

Sounds like some sort of exhaust limiter for hot and cold engine running mode. It needs to be re-attached or replaced.

Sounds like you have a freeze plug that has rusted out. And it is located in side the bell housing behind the flywheel. You will need to remove the transmission and the flywheel to gain access to the freeze plugs. There are two of them at the rear of the engine above the center line of the crankshaft. One to the left and one to the right.

Had any recent work done to it? When I had my transmission replaced the mechanic actually tuned it to idle at too low of a rpm so it would idle hard except for when in neutral. If so have your mechanic look at it and tweek it. If not then it might be time for new spark plugs and a good ole fashion tune up. Including all of your filters changed and possibly your injectors. Just some food for thought!

May help if you raise engine a little. But the other freeze plugs are most likley in same shape.

his water pump froze. it blew the freeze plug and then the pulley locked up, it needs to be replaced