Newbie alert...please forgive me if I sound dumb :-)

I have an '06 with the 5.4 and 109k. I'm on my holiday road trip and the engine light came on. Got the code scanned and it said lean bank 1. Just for good measure I changed all four O2 sensors. Light is still on.

Also for the last ~7-8k miles it's done the engine misfire/hiccup thing that I've seen mentioned in other places online. It mainly happens when under a load between 40-50 mph but the light never came on until just the other day.

I'm averaging 13mpg on the highway which makes me think these things are all somehow related.

Your thoughts are appreciated.

 

You have a misfire.

 

So how do I go about fixing that?

 

When were all the plugs changed last? Or how many miles on the plugs now?

Could be just coil packs that need to checked out and/or replaced.

 

I've only owned it since July, it had 100k when I bought it. Don't know the service history before then.

 

if you have a lean condition then look for a vacuum leak. First suspect is the pvc system. the elbow at the back of the engine. I use starting fluid to hunt for the vacuum leaks.

 

You could drive it hard, hitting a lot of hills and wait until the CEL come on and gives you the misfire code, then you'll know exactly which cylinder is doing it. The other option is to get your hands on a code scanner that reads live data, connect it and go for a ride. The live data will show the misfire counts per cylinder and the high count one will be the problematic one.

 

FYI, 100K is the Ford maintenance schedule spark plug change interval. I'm sure no one changed them right before selling it, so changing the spark plugs should be on top of your 'to do' list, and it might also be the root of your current problem.

 

Today's update...it was weird.

I planned on replacing all spark plugs and maybe coils this morning. As I drove to Autozone, the CEL was off and the Expy drove fine. I was confused but a little excited. I bought everything for an oil change and came back home to do that.

Afterward, I had some errands this afternoon. I intentionally drove it a little harder than normal (ex: hard accelerating onto highway) to try to force the bucking condition to occur again. In total I drove about 30-40 miles today. By the end of the day, the light was back on and all symptoms resumed.

I stopped at a NAPA certified mechanic to pick his brain. He said I, unfortunately, wasted money on the O2 sensors and that he was "very certain" that it was a vacuum hose leak. He said I could get the hose assembly from the dealer for about $50 or that they could do it in about an hour for $189. I'm leaving town tomorrow morning for work and won't be able to do anything on it until Friday, at best. I'm going to think a little more on whether I want to do it myself or have the pros tackle it for me.

Anyone have experience on replacing the hoses?