I have a 1999 Ford Expedition and it started missing about a week ago and has progressively gotten worse, but it only misses when you accelerate or the engine gets in a bind (like going up hill) any...
How many miles? Have you ever serviced the spark plugs? I will assume it's a 5.4 V8, since it's more common than a 4.6.
In my experience with 5.4's, at about 120-140k miles, the coil-on-plugs tend to start dying. You will only feel the miss on acceleration and under heavy load, but may feel a slight wobble when the truck is at idle.
Not knowing how experienced you are with vehicles, I will give a slight overview. The traditional older vehicle has a single coil that delivers high-voltage to all of the spark plugs to cause the spark and ignite the fuel in the cylinders.
On these newer vehicles, each spark plug has it's own coil that is attached to the spark plug.
Unfortunately, there is no easy way to determine which coil is not firing without unplugging the wiring harness on each coil and seeing if the behavior of the engine changes.
However, in my experience, once one coil dies, the others aren't far behind. It may be worth your while to change them all at once.
The downside is, they are not cheap at about $43/ea at autozone. The upside, is they are extremely easy to change yourself. Simply unplug the electrical connector off of each coil at the spark plug. Then remove the 8mm bolt that holds down the coil. Pull off the sparkplug and replace.
I changed a full set in the parking lot of a hotel in South Fl last year, and it took me about 1 hour.
Jan 01, 2010 |
1999 Ford Expedition