Here's a little back ground on my problem. I have an 03' expedition 4.6L. Last week my wife was on the highway when the engine light started flashing and the engine start surging. She got off the highway and it ran fine if you didn't push it and the engine light stayed on.

I didn't have a code reader but the owner manual said it was a mis fire. I also checked this site for some ideas. The oil was about a quart low too, so i gave it a tune up. Changed plugs and oil and air cleaner, cleaned and checked IAC good volts and resistance. Also cleaned and checked egr valve with vacuum gauge, also passed.

When i went to disconect the battery to erase codes i found the pos. cable lose, cleaned and tighted.

Still surging when you get on it, the other day i took it out and got on it and i lost power, i pulled over into a sub and it stalled out. When i restarted it, it ran fine but still surges when you push it too hard.

The check engine light is not on and i borrowed a code read and got code 354, 355, 356, and 358. My question is do i check the coils by pulling the two wire plug while the engine is running? Do i have to worry about a high voltage shock or frying anything? Also how do check the egr pressure sensor, can i just unplug the egr vacuum line and plug the hose with a golf tee and see if the surging goes a way.

Didn't wash engine bay or see any water when i changed the plugs..

Thanks all who answer.....

 

Even though you have specific cylinder misfire codes, it sounds like a fuel delivery problem to me.

 

Great point, hkiefus. I was perplexed at the multiple misfire codes. JoelnKim, how's your fuel pressure?

 

When was the fuel filter changed?

 

Replaced fuel filter and it seemed to help for now, we'll see.

Thanks