I have looked thru quite a few other posts, have seem some similarities, but nothing quite like what I'm seeing with my F-150.

I have an '04 with the 5.4 3v V8. When I accellerate from 45 - 60 mph, it misses bad (really bad) and the truck shakes. If I take the over-drive off, it seems to improve, but this kills my gas mileage.

No check engine light has ever gone on. I finally got a shop to drive it with a computer hooked up, and they said it was a problem with the #1 cylinder missing. I changed the plug out and put in a new ignition coil as well, but same problem.

Truck has 156K miles on it. I had the spark plugs changed around 120K miles . The plug I pulled out of the #1 cylinder seemed to have some burn markings around the middle of it, not sure if that is just normal carbon buildup or not.

I really don't want to have to go thru and throw $ at it by replacing every single ignition coil. I've pulled them all, no discoloration of the spring, no dry rot on the bottom of the boot, no visible problems.

Anyone else seen this, or have any suggestions on how to find out if another cylinder is also missing, or which ignition coil could be bad?

Thanks for any assistance.

 

coils aren't to expensive if you get them on E-bay. No check engine light? I'd replace all the coils and if it doesn't have Motorcraft plugs I'd put them in..

 

thanks for the feedback jethat. I will try the coils first. No check engine light has ever come on. I did put di-electric compound on all of the ignition coils to try and see if that didn't help the connection out, but no luck. So I guess I'll try coils next and hope one of them is just bad, and this clears up the problem.

 

http://www.ebay.com/itm/Visteon-Moto...aac312&vxp=mtr

 

What brand of plugs? Also, make sure you have replaced the fuel filter in the last 20,000 or so miles and clean the MAF and throttle body.

 

^^^ Can you eloborate? It's an insulator... here's the proper way to apply it:

=> https://www.f150online.com/forums/4829957-post17.html

From this thread: https://www.f150online.com/forums/v8...lp-needed.html

BTW - new boots are always a good idea. They ain't expensive. Just fyi.

Good luck!

 

sounds like a possible bad coil boot or cop.....

try swapping the suspect bad coil to known good cylinder and if the miss follows then you'll know what to replace...

 

they told me the #1 cylinder was missing, so I replaced the coil and plug in that cylinder, but still have the problem. So I'm guessing it is another coil that could also be bad.

It has Autolite plugs that a shop put in about 35K miles ago.

I found some coils online that were much cheaper than O'Reilly's, so those should be in next week and I'll try that next. Wouldn't think it would be the plugs with only about 35K miles on it.

The throttle body is clean, but I will check the fuel filter, thanks for that reminder Bluejay.

Anyone had issues with fuel injectors? Never messed with those, not sure how hard they are to clean / replace. I run cleaner thru a couple of times a year, but not sure how effective that stuff really is.

 

thanks for the info MGDfan. I put it on the end of the coils. That is what a guy told me to do, said it made a better connection. From the sound of your post, that isn't where it should be though. Guess when I replace the coils, I won't be doing that with them.

 

The grease goes inside the boots - you do not want to get it on the springs.

I'd replace the plugs with Motorcraft SP515's. Cheap Ebay coils may or may not work well, we have been recommending Visteons at about $180 a set. Those are essentially OEM, Visteon is European Motorcraft.

The best fuel system cleaner is Techron.

 

This

replace with motorcraft sp515

 

I changed my timing tensioners ,cam phasers,vct solinoids,and all spark plugs!!! My 5.4l engine in my 2008 f150 is rumbling struggling to stay started. But when i unplug the vct solinoid it works fine no rumbling . But if i plug it bacvk in it goes back to struggle to stay on when i come to a stop light . What is the issue i'm out of thoughts!!

 

Wow - all that for a 2008? How many miles?

All I can think of is cam timing. I'd start by checking the valvetrain indexing.

Good luck

BTW - it's may be prudent for you to start your own thread and not jack this one. Thanks.

MGD

 

I have the same issue, mechanic says I need plugs and 1 coil pack. Wants to charge $550 for parts and labor. Oreilly has coil pack for $45.00. I'm debating whether to change coil pack myself and forego the plugs for now, or just pay the $$$ and have it all done. I hear nightmare stories if getting these plugs out of 2004 f150's. Any suggestions would be appreciated.

 

Might be shooting in the dark, but have you checked the ERG valve? The valve directs a small portion of exhaust gasses back into the inlet air charge and lowers the maximum temperature of the burning fuel. The valve makes sure that the EGR system is off at idle, where it would lead to erratic and loping idle, and at peak power, since adding exhaust gasses robs power from the engine? Just a thought.