I have a 2014 F150 XL with 5.0 8cyl engine with tow package. When I tow my travel trailer up any hills, the check engine light comes on. A stop at an auto store reads 300 codes or fuel injector misfires. We cleared the code, and put in gas line fuel injector cleaners. Light stayed out during normal driving (no trailer) but went on again the next time I had my trailer connected and went up a hill. This time, after a while of driving without the trailer, the light went out by itself. I've put in some more fuel injector cleaners into the gas tank, but I'm not sure if I still have a problem. Any idea what is causing this? Truck has just over 150K miles and I just spent over 4K on a transmission rebuild. I've had the trailer for 3 years, it weighs around 5000lbs, truck is rated to pull 7800 lbs. and this problem just started happening.

 

May be the injectors finally needs to be replaced? At least the one with the misfiring cylinder?

 

What do you think made your transmission fail? I have an 11 with 224K on it, regularly pull the skid loader on the interstate, and it's 8,000lbs with the trailer. The truck was rated for 11,300 the way it came from the factory. I've never had a transmission issue. I'm ready for a second timing chain and wondering if I should just get rid of it or put in another chain and see if I can get 300K on it? As far as the light, I can't say on the 5.0, but on the Ecoboost that was sometimes a sign a coil pack was going to fail. The engine light will go out on its own after no codes for a while.

 

I was driving (no trailer) and I suddenly get a bang out of the rear and a "monkey wrench" image pops up on my dash. suddenly it feels like I can't get out of 1st gear. Pull over and shut off/ restart the engine, and it runs fine for a while, then same thing happens. Went to Ford dealer who wanted $6500 to repair tranny. went to local tranny shop (not chain) who tried 1200 fix for the one part that kept throwing the code, but that didn't hold, so replaced the whole thing for 4500.

 

Wow, 119 views, and only one person suggesting injector replacement? Is that easy to do? Has anyone else had this issue while pulling a load up a hill? If the check engine light goes out when driving without a trailer, does that mean it's really not a problem? Can I just ignore it when I'm trailering?

 

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Agree with checking air filter to make sure it is allowing enough air in and cleaning MAF. My misfire 300 code was a MAF issue.

Did you already say what gas you run when towing? Regular? Premium?

 

When were the plugs and coils last done? Engine under load seems to be the classic symptoms of coil failure. CEL may go out, but you’ll still have codes stored and Fords are pretty generous as far as misfires not tripping it on until they get pretty severe.

Anyway, to avoid a misfire, you need proper fuel, spark and compression. What are you missing?

 

Thanks. What is the MAF? I run regular fuel and rarely let it go below a quarter tank. I will check the air filter. I bought this used and I don't think sparks or coils were ever replaced. Is this an expensive thing to do. Does it involve the "phasers" which are supposedly very expensive to replace (like get a new engine expensive)?

 

Mass Air Flow sensor. It's connected to the tube of your air filter. Check out videos, it takes a torx bit and $5 MAF cleaner and 10 minutes.

Though I would also try running premium fuel when towing. That seems to be the consensus to avoid things like misfires. Should be able to Google research about it.

Edit: If spark plugs haven't been done at 150k, I'd also have a look at them and also inspect the coil/boot that is on them. If coils look good, I'd leave them be for now. Replace any that look damaged.