2003 ford expedition has service engine light on

Has it had a tune-up yet? (New spark plugs) If not, you're due. Also, have the shop test your coil packs - a very common problem with the Expeditions. I had my plugs replaced and No. 2 coil pack replaced recently for around $340. I'm a handyman, but would never attempt to change the plugs on mine myself - too much could go wrong- breaking a plug off, special tools, etc.
This should fix your problem.

will try to help.the shaking during braking may be a warped brake rotor,shaking while driving is in the wheel alignment. you have several issues to deal with.as far as the engine light flashing,check all your fluid levels in the engine. oil,low coolant, brake fluid,transmission fluid. top off fluids as needed. you can reset that engine light by disconnecting the positive cable from the battery for 10mins.this will reset the cars computer. but if you have a sensor or other issues,that light will come back on.the only way to know for sure is to have it code read a garage or dealership will be able to plug it in to get the codes for you.hope this helps and thank you for choosing fixya.com

If you do not see a distributor or spark plug wires, then you have a coil over plug system. Changing the coil pack is as easy as removing the hold down bolt and lifting the coil pack off the spark plug. Other things should be checked like signal to the coil, the fuel injector signal and the spark plug

Remove coil covers,then coils,then plugs.

Third cylinder back on the passenger side. I'd recommend changing all 8 coils and spark plugs. These coils don't last long, and once one goes, more will fail soon after. This job also requires removing the fuel rail to gain access to the coil and plugs. I personally have the same SUV and went through the same issue!!

Check this for 4.6 or 5.4 sizes engine...

2004 Ford Expedition 4.6 liter V-8 VIN "W"




2004 Ford Expedition 5.4 liter SOHC V-8 VIN "L"



Hope this help (remember comment and rated this).

Its recommended to replace all coils at the same time you replace the plugs. I had the same problem @62000miles, changed the same part, including injectors at the ford dealer. It just got worst, I replaced all the coils and engine ran like new.

there isn't a trouble code that indicates a bad coil... there are misfire codes that can possibly lead to a plug, coil, fuel injector, low compression, or a number of other things. it is possible to have 2 more bad coils-if youve had the engine compartment detailed and they got them wet, that'll do it. other than that it is hard to see 2 coils going at 1 time. spark plugs themselves are more likely.

check pass side rear plug the coolant hose the runs to the heater core can leak coolant into the rear spark plug boot and cause a miss

Changing the spark plugs on a 1997 Ford Expedition 5.4L engine takes patience. Remember to start this project on a cold engine! I started on the passenger side by locating the Coil over iginition coils and cleaned out all the old dirt using some compressed air. Then I had to disconnect the electrical connections to both the Coil over ignition coils and the passenger side fuel injectors. Once you remove the small bolt which holds the ignition coil in place, use your compressed air again to blow out the spark plug hole. After that, you will need a 5/8" swivel spark plug socket and various length extensions to remove the spark plugs. Take your time because there is not much room for your hands. Before installing the new plug, check the gap and use clean engine oil on the new threads. Tighten the new spark plug and reinstall the coil over ignition coil. Reconnect the electrical connection to both the ignition coil and the fuel injector. Continue these steps with all eight spark plugs. You will find the ones on the drivers side are difficult because of the fuel rail gets in your way. Have patience and use swivel extensions to work around the tight spaces. When you are done, you will have saved lots of money! Don't forget to replace your air filter, fuel filter, and pcv valve to complete your tune up.