My 06 f150 5.4 3v has developed this miss in the last 1000 miles which is very annoying and fuel consuming. Its most noticeable at idle where the engine quivers and at highway rpms where it will start to vibrate when being slightly worked. I have already changed the cops and plugs, and there are no codes coming up.
thanks

 

Thats odd that there are no codes coming up. Maybe try unplugging each COP, one at a time to see which cylinder the miss is on. Also, if your scan tool does live data, look and see if the engine is compensating like there is a miss somewhere. I believe Ford also provides miss counter for each cylinder that can be read with a scan tool.

I am wondering if it could be something else that makes it feel like the engine has a miss, like a broken motor mount.

 

I've tried unplugging them and there doesn't seem to be a difference between cylinders. Our shop has a 2005 Mac mentor or something, what do you mean by live data. I haven't seen ant miss counter on the tool.

 

Live data is the data feed from the computer showing all the readings from the sensors on the engine (e.g. RPM, idle, throttle position, ignition timing...). You said the truck was using more fuel, therefore you should see higher fuel trim numbers. The fuel trim numbers are shown for each bank, therefore you can hopefully narrow the miss down to one side of the engine. The misfire counter is on more expensive scan tools, and shows how many times each cylinder has a misfire.

this article may help also.

OBD II Code P0303 : RepairPal

 

heres some pictures of the fuel trim, and knock sensor readings.
2012-05-06095129.jpg picture by BrandonOrban - Photobucket
2012-05-06095129.jpg picture by BrandonOrban - Photobucket

 

I have no idea what the problem would be. I don't know how to interpret the knock sensor data from the scan tool. You are also showing negative fuel trims, which means the computer is reducing the amount of fuel going into the engine, so I am not sure why your fuel mileage is poor. The fuel trim numbers are in an acceptable range too.

 

Look for damaged wiring rubbing on metal, maybe by the hyd pump or back of motor. Look at your Catz temps. A low temp will be a clogged one while a very high temp will be a rich mixture to that bank. Look at your O2 comparisons between banks and upstream or downstream. That would affect fuel mixtures. Swap your cops and fuel injectors 1 at a time until you narrow it down. Sounds like a couple bad cops or wiring. Also check your transformer capacitors, one on each bank for ign dwell, look to their wiring.

 

hey papa, quick question, your saying the transformer caps could cause odd miss, how about problems on the cops?
I have an on going issue on my 05 fx 203000 miles, new plugs , new coil, also new cam sensors.
I keep chasing the p0354( sometimes 355,356,358) code.
only way i can run the truck is with the cam sensors unplugged, if not very rough idle and of course no power.
reason i am asking is because a little prior to this I was hearing interference accross my radio???

 

Did you replace all boots on plugs . Clean all cop contacts. Mode six has raw computer counts per cyl towards setting a cel . Under torque pro its in test results . you must do a hosp clean plug job . Plugs are very fussy on this engine . Boots are a high failure item ,people just don't want to change them . They are not expensive .Every plug job at 60 k change them . Torque all plugs 25 to 28 foot pounds .Not by feel .Go easy on that dielectric grease .

 

yes sir Red, all new plugs(will recheck torque), new cops.
I have a centech scanner from harbor freight which I believe is made by autel and I am not sure where to fin the mode 6 info

 

We have a 2007 5.4 that showed similar problems again in hot weather. Last summer it was MAFS which almost fixed it until now. It started the rough idle, almost stalling event again. Local shop (very good mechanics) found the a/c tensioner loose on the belt. Replaced both hoping that it would fix it, but also noted a/c compressor might be at fault. And it was. They did an "a/c replacement kit" with Motorcraft parts. All is well again and I think the a/c had been dragging down the engine performance for a while. Runs smoother and idles perfectly, peppy again. The mpg is much better again too. Hope this is not your problem - it is expensive. This truck has nearly 170,000 miles on it and lives in desert southwest.

 

yea hope it isnt the AC issue, I dont think it is as it runs pretty decent with the cam sensors unplugged(they are new)