Test revealed cylinder 5 is missing on my 98 expedition

SOURCE: Truck losing power and service engine soon light on

Like to other guy said, give it a tuneup. Also try SEAFOAM to clean carb up of slug. Also check to make sure the butter fly for the choke has not come loose, causing it the choke it down. Failed choke pull-off.

SOURCE: 98 chevy 1500 4.3L vortec misfire problem

These have a real problem with the distributor caps, i would try that

SOURCE: "check engine light flashing"

The flashing check engine light is typical of a misfire issue. There are two things I would do to start with.

1. Take the vehicle to an auto parts store like Autozone and have them hook up their scan tool so that they can retrieve stored trouble codes. Even if the check engine light is not on, they should be able to retrieve recently stored codes.

2. Do a complete tune up. New plugs, new plug wires, new air filter, new fuel filter if it has not been done recently.

If the parts store pulls the codes and they cannot tell you what they mean, post them up here and I will see what I can dig up for you.

SOURCE: 2000 vw bug shaking and check engine light flashing when driving

You have a really bad misfire going on. i would not drive the car but if you get it towed you can get the engine codes read which will give you more of an idea on whats going on. Otherwise its just a guess.

SOURCE: Saturn Ion shakes when started.

I would take the vehicle in to a mechanic.
There could be damage internally with the engine.
or the transmission.