[KEBusch]

I have a 2008 Ford E150 4.6. It has 179,000 miles and has been well maintained. Recently, I was on a 250 mile round trip service call. It drove perfectly, as normal all the way there. But, when I started it to leave, it had a noticeable miss. The miss seemed to come and go. When I returned, and shut off the engine for about an hour, then restarted it, the miss was much more noticeable. So, I stopped by the auto supply to get the codes from the check engine light that had come on. It showed misfire on cylinder 2 and 4. Knowing the spark plugs were replaced less than 50k ago, I purchased 2 new coil packs and installed them. After the installation, it was better, but still missing. Had the codes read again, then it showed misfire on 2,4,6 and bank 1 running too lean. They cleared the codes and read them again. Now it reported misfire on 2,4,6,and 5, and bank one running lean and random misfire.
I ran out fuel from the tank, added new fuel. Changed the fuel filter, changed the oil and oil filter while I was at it, along with the air filter.
I'm still throwing misfire codes across the cylinders. It will idle smoothly for as long as I want. But it cannot handle the load of putting it in gear. It will run and drive, but it misses badly and cannot seem to get above about 35 mph. Additionally, under load, around about 15k rpm, it develops a high pitch shreek that will last for a bit, and then I hear, what sounds similar to a backfire, and the noise stops for a couple of seconds, then repeats the process.
Completely lost here.
Any advice?

 

[85ltdcrownvic]

Check that the plugs are torqued to the correct value before doing anything else. They are known to back out. Also it’s possible that the cats are clogged or the maf isn’t reading correctly. Buying a vacuum gauge and taking readings will rule out the cats.


Sent from my iPhone using Tapatalk

 

[R.S.LOGAN]

Check for vac leaks , pull the plugs and check for condition and any clues .Check inlet manifold , PCV valve and hose .Check for partially plugged exhaust or cat , the high pitched noise can be caused by the gases being forced to seek alternative escape route . If still having problems , check compressions .

 

[ggalloway303]

Sure sounds like fuel pump giving up the ghost to me......possibly plugged pickup screen sack in tank. I see this is older thread.....wish he'd posted resolution.