I have a 2003 Expedition EB 5.4L Last weekend I started the truck and was putting it in 4HI when the CEL came on for a P2198, P2196, I cleared the codes and went on with things thinking that it was chilly, I just started it and was already putting the load on it with turning on the 4wd and going up a hill. Well today while on my way to work driving straight with no real load on it the CEL came on with P0304, P2198, P2196, P0133. All 4 O2's are newer 01/10, and the upper 2 have been redone around 06/10. I am thinking there might be something else that is triggering this. Any help is appreciated.

 

The P0304 code means #4 cylinder is misfiring. A misfiring cylinder will also throw off the O2 readings.

 

plugs are all new, maybe a coil issue??
what else would trigger a misfire... IAT, MAF/MAP???
BUt thanks alloro - that narrows down to the misfire, which is triggering the O2's so I can rule out O2's.. Now just need to figure out what can cause the misfire... :-(

 

A new plug can be defective so although it's unlikely the plug, don't necessarily dismiss it. Other than that, I would next suspect the #4 COP, then the injector.

BTW, the #4 unfortunately is the back one on the passenger side...the hardest one to get to.

 

Thanks, I know that one well.... I am the one who replaced the plugs about 3 months ago...it is not friendly.... I will replace that again though, as that is the least expensive repair, and move forward from there..

Thank you

 

First you might want to swap the #4 COP with the #1 COP to see if the misfire moves with the COP. If it does, you get to replace the COP on #1 instead of #4 and save yourself some repeated grief.

 

so 2 weekends ago I replaced all 4 plugs on Bank 1 and the COP for Cyl4 and today I got a cylinder 4 misfire again... any thoughts... Injector?? or another sensor issue?

 

Check to make sure you do not have a leak in a heater hose connection that is located right over top of #4 cop/plug. This is famous for shorting out the cop.

 

never would have thought about that.... awesome thanks I will check it out when I go to lunch