I have a 1996 ford thunderbird lx. 4.6 engine. When I start my car the engine runs fine but as soon as the engine is warm and I put the car in drive it dies right away even when put in reverse. I have replaced coils spark plugs wires. When computer is hooked up it reads cylinder 3 misfire. What could be causing this?
If the ignition components are good and functioning properly, that only leaves two things that can cause a misfire on that cylinder. The first would be a bad fuel injector, which is probably the most likely if you're sure the ignition parts are working good. The second would be a mechanical problem inside the engine, such as low compression due to broken or worn parts in the cylinder head or piston area. If cylinder 3 is a 'dead hole', meaning that it misfires constantly under all engine loads, then would either have an injector that is stuck/failed....or....a valvetrain/cylinder head/mechanical issue. Either of these would require some extensive checking and testing.
GM Dealer Technician For 18+ Years In the automotive industry for 20+