1999 Expedition 5.4 #3 cyl misfire

[dannyboy1961]

I recently got gas and the next morning truck started jumping up and down going down the road. I believe that I got water in the gas that day.

Have tried adding fuel additive and a little alcohol when putting gas in (2 times). Things have improved somewhat, but now I'm getting PO303 code #3 misfire and still running pretty rough. I'm kinda new at the repair end as my partner always did the physical work, unfortunately he passed away recently. What should I check to try and figure out my problem, or will it inventively go back to normal with time?

 

[Billme]

In case it’s not the gas, I wouldn’t check to see if there is any water from the heater hoses leaking first..If good, switch a coil from #2, and see if it moves the misfiring.. If no change, pull the plug and see what it looks like.. If you have a camera probe, would be better..
So many variables, but this is a start ..

 

[jr1under]

but now I'm getting PO303 code #3 misfire and still running pretty rough.

I've encountered several P030x codes on my 99 and each time was due to a faulty ignition coil. Billme's suggestion about switching coils is good because they're simple to change once you get to them and #2 & #3 are easily accessible. If you do find that it's bad, make sure to replace it with the same brand and model as the other three on that bank.