I love my F150, no question about it. Very reliable and got if for a great price.

Starting at 110k I noticed the truck lurching a bit, or getting shaky at low RPM's when trying to accelerate. Took it in, had the 100k spark plugs replaced, problem solved.

I'm at 140k now and it seems to be doing it again. Just not smooth at all when trying to accelerate. When maintaining speed or idling its as smooth as they come. Interesting enough I started my truck today and literally had a spark plug come out of a cylinder! Terribly loud sound, really concerned about a serious problem, but after looking under the hood I realized the problem, reset the spark plug, reconnected the wire, and the truck fired up without problems. Initially I figured the prior performance issues must have been because the spark plug had been loose all along and was excited that this might fix it. It seems though that this is not the case, as the truck is still shaky and unsmooth during acceleration.

What's going on with my truck? Anyone had this issue before? I really love it and have no intentions of replacing it, but would like to figure out why it's not performing well when accelerating.

Thanks,
Cameron King

 

You may have to put a Timesert in the cylinder the plug blew out of, good chance it's going to blow again.

Whoever installed your plugs did it incorrectly. You use Motorcraft plugs, NO antiseize, and torque them to 28 ft/lb.

I would retorque the rest of the plugs IMMEDIATELY before you blow another one.

Do you have plug wires or a coil on top of each plug?

 

glc,

I assume a coil on top of each plug. When the plug blew all I initially found was a 3" rubber tube and a plastic piece with a spring attached (The plastic piece was circular and had 2 wires coming into it; it was initially screwed down but was no longer because the plastic had broke). I dipped the rubber tube back into the cylinder and the plug came right out with it. A totally different spark plug wire system than I have ever seen.

Do you really think that I can expect more plugs to blow 30k miles after they were replaced? If so I will take it back into the shop that replaced them and have them redo it. They are respectable folks that will understand their error.

 

Yes, those are coil on plug.

What happened is this - the heads only have 4 threads for the spark plugs. The factory torque specs are too loose, the plugs vibrate loose and blow out, frequently stripping the threads in the aluminum heads when they go. The use of antiseize only compounds this issue. Motorcraft spark plugs have nickel plated threads, eliminating the need for antiseize.

You may have screwed the plug back in, but if the head threads are damaged it's only going to blow out again. If this happens, you will need a thread insert installed. Helicoils do NOT work, they will just blow out again. The only inserts that last are Timesert and Lock N Stitch. They can be installed without removing the head.

If the shop did not use Motorcraft plugs, have them replace them with Motorcrafts, do not use antiseize, and torque them to 28 ft/lb. The broken coil will have to be replaced. They must inspect the hole that blew the plug, any thread damage must be repaired with one of those 2 inserts. It would be wise to check the rest of the plugs for looseness, if any are loose those threads must be inspected.

Reference:

www.blownoutsparkplug.com

FAQ's #51 and #52 in particular.

If the shop tries to tell you that you don't know what you are talking about, go to a good Ford dealer. They should be WELL aware of this issue.