Voilà ce que j'ai trouvé sur le net :
(en anglais)
You check 3 things, ignition, fuel, compression.
You've changed plugs you've swapped coil's, you've changed ignition control modules. Ignition is taken care of for the most part, unless theres some weird Crank position sensor causing the pcm to not determine when cylinder 5 is supposed to fire, or if the pcm itself is fubared.
Fuel your obviously getting good pressure if it's isolated to a single cylinder, so that leaves injectors, you've swapped injectors and it's still isolated to cylinder 5, so that rules out fueling.
Your left with compression, compression test it. Warm the car up. Pull your fuel pump relay, pull the plug ground it to the block (use a spark plug style spark tester, this makes your life easier so you don't have to disable the ignition system though you still risk slight mishap since the system isn't disabled) hook the compression tester up have someone hop in the car hold the gas pedal down and crank it over for about 10 seconds while you monitor the compression gauge.
I'm not sure what our compression should be but from the thread i'm guessing around the 180 mark.
So if your not hitting proper compression take the tester off squirt like 2 tablespoons of oil into the cylinder through the spark plug and retest. If you get compression then your rings are fuck.
If your still not getting compression then it's time to do a leak down test to measure cylinder leakage. You'll need a leakdown tester and a air source to pressurize the cylinder to like 90 psi while the cylinder your testing is at top dead center. a leaking sound out of the throttle body means intake valves leaking, out the tailpipe exhaust valves leaking. Your going to have leakage since nothing is perfectly sealed, but below 30% leakage usually means your ok.
Headgasket gone, worn cam lobes, collapsed lifters, broken valve springs.
Since you said you experience white smoke out of the tailpipe upon start up until the engine warms up that leads me to believe you might be burning coolant most likely through the headgasket, so then your onto bad head gasket block warped or head warped.