While driving 45mph on Suburban two lane highway I heard a loud bang and subsequent rhythmic popping sound accompanied by an engine misfiring. Upon inspection I found the # 4 cylinder spark plug lying on the valve cover; un attached to the cylinder head. The mechanic found the threads "blown out" of the head and had to utilize a heli-coil kit to repair. The spark plug was a motorcraft original equipment part. This seems to be a prevalent problem with the Triton 5.4 liter engine. I suspect the problem originating from undue stress fractures in the aluminum head after continued use and inherent thermal differential rates (expansions/contractions) of the two different metals; I.e. steel spark plug vs. Aluminum alloy head. Poor engineering !! I am the original owner of the F150 with 140K miles.

- Ozark, MO, USA

Blown spark plug from Ford Triton V10 engine which can cause a major fire in the engine compartment.

- Glendora, CA, USA

I was driving my 1999 Ford F150 4X4 with 5.4L engine home from work and stopped at traffic light. The light turned green and I proceeded to go and then "pow" the truck began to make a loud "popping" noise and lost all engine power. I was in the middle of the intersection and somehow managed to keep it running long enough to get through the intersection and on a side road. I hesitated to open the hood because of the strong gasoline smell but it wasn't on fire "yet" so I opened it and found one of my ignition coils (coil packs) loose on top of the intake manifold. Upon further inspection I realized the spark plug had blown out of the aluminum cylinder head. I was able to catch a ride to the auto parts store with coil and plug in hand. The salesman at the store immediately knew what had happened and even knew the engine was a 5.4L before being told. He said that if I was lucky I would probably just have to install a helicoil or threaded insert in it. The other option was to replace the cylinder head. I purchased new coil and plug then drove back to my truck. I tried to clean the threads with a spark plug thread chaser but there were no threads left to clean. I searched the web and found numerous complaints of the same issue. Some people said they had multiple spark plugs blow out or "spit out" on the same vehicle. Why doesn't Ford have a recall on this" the gasoline smell was due to the fuel injector still spraying while the plug was blown out of the head. What if it had caught on fire" I haven't repaired it yet but will try the "repair kit" that was handed to me when I bought the coil and plug. I think Ford should recall all the 5.4L engines that have this problem and install the helicoil or insert to prevent a customer breakdown or a potential vehicle fire.

- Kearney, MO, USA

Spark plug blowout on 1999 Ford F150 with 5.4L Triton V8. It seems to be a very common problem with the Ford modular engines. Today, I heard a loud pop come from my engine bay as I accelerated and then the sound of what seemed to be a massive exhaust manifold leak. Upon further inspection, I found that the spark plug on the rear passenger side of the engine had ejected and broke the coil with it. I was lucky that it had only damaged the threads on the spark plug and sheared the coil at its mount, instead of damaging the threads on the head, but from reading the multiple other stories online about this happening, it seems that I am luckier than most. I was able to repair it by replacing the spark plug, boot, and coil, but from what I have seen, most people have to replace the head when it happens. I don't see why there has not been a recall since it can cause an accident due to scaring a driver when they hear a loud explosion in the engine when it happens, or possibly killing someone as fuel/air vapors escape the engine and the spark plug could possibly ignite it outside the engine, and being right next to the fuel rail and injectors, possibly cause massive fire damage with its occupants still inside the vehicle. Please tell Ford to recall this problem. I see the fix being as simple as putting stronger thread inserts to prevent the spark plugs from ejecting. Its ridiculous us as car owners should have to continuously pay big bucks for a faulty engine design that Ford refuses to acknowledge or fix.

- Portland, ME, USA

Accelerating on ramp to freeway heard a loud bang, vehicle lost power and engine ran rough while making loud unmuffled noise. Found that vehicle had blown out #6 spark plug. Ford F-150 with 5.4L engine, with 120,000, original owner. Found numerous internet postings on this problem. Contacted manufacturer, no recalls or assistance. Makers fix is to replace heads, at customer expense. Found shop offering in vehicle repair, and expect repairs to be done shortly.

- Runnemede, NJ, USA

On four separate occasions, the vehicle began idling and accelerating roughly for about 2 days. The check engine light would come on after about a day. The problem would stop and the light would go out before I had the chance to take it to a shop. This last time, March 27, 2009 it had been raining for a day or two. I went to start the truck and the engine was idling and accelerating roughly again. Upon taking it to a local repair shop, I was told that the rear two coil packs had failed and that this was a common problem with this model. It was explained to me that the rain run off from the vehicle dripped onto the rear two coil packs and would cause premature failure. The problem started at about 71,000 miles and was repaired at just over 72,000.

- High Point, NC, USA

Went outside to start my truck 1999 Ford F-150 5.4L. As soon as I started the truck I heard a loud banging, shut the truck off, open the hood, and a spark plug had blown out the head ripping all the threads out and breaking the coil. So now my $14000 truck is useless. My only options include $3000 for new heads or a heli coil kit which will eventually allow the same problem or worse to occur.

- Woodward, OK, USA

The number 3 spark plug blew out of my 1999 F150 while pulling away from a stop light. The aluminum head has only 4 threads holding the plug in place, clearly a design defect. I had both heads removed and had all eight holes repaired...total cost was about $3,000. There was 80,000 miles on the truck at the time. Ford should stand behind their product!

- Winona, MN, USA

My 1999 Ford F150 ejected a spark plug - damaging other parts as it ejected - this is a manufacturing defect that needs a recall a fire can easily happen in this situation.

- Mansfield, OH, USA

Spark plug blew out of cylinder head while driving down the highway. The thyreads in the cylinder head were sheared off. This vehicle (1999 Ford F-150, 4.6L engine) has not been fixed due to excessive costs of repair.

- Troutman, NC, USA

While driving to work at 5:30 am, a load noise came from the engine compartment. The truck would barely run and required a tow, the dealer ship said that the spark plug had ejected from the engine due to stripped threads in the block. Also I have complained about the truck losing oil and the smell of burned oil on an off since I purchased the truck in 2000. The dealership could never find a problem. The leak is now worse with oil on the garage floor for the past year and the smell of burned oil more often. I suspect the head gasket from reading other reports on the internet.

- Woodstown, NJ, USA

Blown head gasket.

- Galloway, NJ, USA

Truck started missing, sputtering, pinging, running on 3 cylinders. Valve spring broke in engine.

- Union City, CA, USA

I purchased my '99 Ford F-150 in the spring of '04. At the time of purchase the truck had just over 49,000 miles on it. This past Monday (10/16/06) while pulling out of a local parking lot, the #2 spark plug was ejected out of the right cylinder head, ripping out the threads that the spark plug screws into & destroying the coil pack located directly above. My truck on the day of failure had 81,790 miles on it. That's 18,210 miles short if the trucks first manufactures suggested 100,000 mile tune-up. Ford will not even consider the thought of making this manufacturer's defect right. They simply told me that the head would need to be replaced at my expense and at the cost of $2,800 to $3,000. It's a design flaw!!! the aluminum heads for the 5.4 L engines were engineered with an inadequate number of threads needed to retain the spark plugs. There are only 4 to 5 threads tapped into these heads (approx. 1/4" to 5/16" in length) today is October 19th and I have purchased a repair kit manufactured by dorman products to fix this stripped out spark plug myself. This kit is specifically made by dorman not Ford, to fix this problem of Ford 5.4L engines. It's really sad that Ford has to use the consumers as guinea pigs and then fail so miserably to back their product. I'm hesitant to check the torque of the other seven plugs in fear that they will not withstand the recommended 25 foot pounds of torque required to tighten them up but if I don't then it's russia roulette as to when the next one will blow out and where I will be stranded when it does. I expect Ford to stand behind their product 110%, especially when it is a well known fact by Ford and the consumer that there is an engineering flaw with the design of the 5.4L engines aluminum heads produced between years of 1997 through 2002.

- Lebanon, OH, USA

I have a 99 F150 with less than 60K miles on it. While driving to work a spark plug blew out. Repair was not able to be done on the head. Head replacement was $3600 engine replacement was $5000. I replaced the engine with the same type of faulty engine... how long until it happens again??

- Mcloud , OK, USA

99 Ford F-150 197K miles. Cylinder #3 spark plug blow out. Almost broke fuel rail. No fire heads replaced. Seeking reimbursement from Ford $3150.

- Geneseo, IL, USA

Oil leak in head gasket due to manafacturing defect. I see many other owners have the same problem. Truck is out of warrenty and repair is very costly. Ford is aware of the problem but is not helping owners.

- Menominee, MI, USA

When I started my vehicle their was a loud popping noise, further investigation showed the #2 cylinder coil was jumping up and down. When I pulled the coil out the spark plug came with it. The aluminum engine head had stripped out the threads that hold the spark plug. Further dealing w/ Ford dealership, as to how to fix the problem, is to replace the head at a cost of $2500 plus.

- Argyle, NY, USA

My Ford F 150 blew the #3 spark plug out of the head on good Friday. The truck lost power but was still drivable. The event occurred on I 39 North of madison wi. Had I not known what to do it may have resulted in an accident. Cost to fix this failure was 4200 dollars. Dealership replaced the entire cylinder head.

- Thomson, IL, USA

Spark plug blew out of engine causing engine head damage. This cost over $3000 to repair and I understand may happen again at any time with any of the 8 spark plugs.

- Rochester, MN, USA