2014 F-150. Check engine light came on last week but with everything going on, I didn’t have time to get it checked. Started idling really rough but still ran fine. Took it to a mechanic who gave it a tune up. Picked up truck after shop had closed and Check engine light came back on within sight of the shop. Drove it about another 60 miles and truck started shaking and check engine light started blinking. I had to pull over and get towed to another mechanic. He calls says both catalytic converters were bad and an O2 sensor needed replaced.

I did make a mistake and put in about a quarter tank of some premium high octane gas thinking that would help. But I found out that is a no-no with those E-85 fuel engines but have tried to run it all out.

Picked truck up tonight and it runs just fine but just doesn’t sound right. Sounds like the engine is just louder now. Should I just drive it a day or so and break the new parts in and make sure all the premium gas is burned out or do y’all think there is still something wrong with engine?

Dr. B

Is it the 5.0 motor or ecoboost?

Some aftermarket converters will make it a little louder if you mean exhaust louder.

5.0 I think. It's not ecoboost. I'm gonna take it back by the shop and let him listen to it later today. You get used to how your vehicle sounds and you know instantly when it sounds different and it definitely sounds different now.


Dr. B

My ecoboost makes one hell of a air noise in the cab when I hit the gas, shop said it was the turbo's but I wouldn't have thought so. You can actually feel air coming up from the floor board.

Not hat it matters, but out of curiosity, what all is included in a tune up these days?

Not calling you a liar, but where did you hear that about premium fuel? And honestly, catalytic converters are supposed to last a long long time. Unless you’ve got a buttload of miles, I’d be looking for what caused the cats to fail, burning coolant, rich conditions, burning oil..... something doesn’t quite add up.

Mechanic told me about not to use high octane fuel and I questioned it. I looked it up in my owners manual and sure enough, it said not to use anything over 87 octane.

Truck has 136k miles.

Back at shop. Check engine light back on.

Dr. B

I just went thru similar issues with my 2014 F-150 with the 5.0 engine. Owned since new with nary a problem, water pump replaced at 100k THEN at 130,000mi +/- started getting check engine light, then wrench light, some other warning lights. 3 different mechanics, 2 different Ford dealers, 8 weeks, & $3k later the truck was still doing the same thing and actually had to be towed in. Every sensor on the engine replaced, throttle body cleaned, catalytic converter replaced, new alternator, new battery, fuses replaced, fuse block replaced, relays replaced, wiring harness, etc etc etc. Long-Lewis offered me $21k as it sat and I couldn’t shake their hand fast enough. Good riddance.

Well that's encouraging.... I may be in the same boat. Long-Lewis huh? Good to know.

Dr. B

If the vehicle is running fine it may be best to ignore the light (put electric tape over it). Check engine lights can be a money pit. The shop will scan it and it will say o2 sensor or cat efficiency or something and you can replace the first thing and the light will come back on and it keeps happening over and over. The wrong fuel can cause that and trigger all of those similar sensors to turn the check engine light on. Family owns a used car dealership and we have to disclose that up front that we will not warranty a check engine light, only an actual issue with the vehicle.

does it have coil packs?

Sounds like the Cald sensor has gone bad. Sorry. Had to say it.

Vvt fords biggest problem. The solonoids go bad and the ecm request gets outta sync with the timing. Usually a new engine will fix it

Not many if any independent shops can justify buying the tooling to fix it and not many dealerships have anyone that can use the tooling they have to fix it

It could be a cam phaser also I guess but less likely

VVT issues are why I decided I wasn’t made enough about the bailout to drive a ford. My F150 and my wife’s expedition went to crap at 130-150k along with about 23 million other VVT engines in the same Mileage range. I got a real good friend that’s been a tech at the same ford dealership over 30 years and hands down the best mechanic I know on gas engines. I ask him how to fix it without buying an engine and he replied “Buy a Chevy, I did”.

I’ve bought several chevys since that day and still think it was great advice

I love my F-150, it's only ever given me one problem. Shimy shake similar to what your talking about. Bad #8 coil pack and its never come back. That being said 3 mechanics gave me what they said was wrong which amounted to huge bills they wanted to charge. Check engine light get the code AutoZone can pull the code and you will know what's wrong

This. the shaking and check engine light with that amount of miles, sounds like a bad coil to me. I would have started right there.

Maybe you gradually got used to how it sounded plugged up and now it sounds different that it's not.

I'm thinking not. That engine was as smooth and quiet as a sleeping baby until yesterday when I got it back out of the shop. When mechanic cranked it up today and it was rattling, he shook his head like "Yep, that ain't right." and drove it back around to the shop. Haven't heard back from them so the saga continues.

Dr. B

All after market parts are not the same. In some cases only a factory part will put the light out. Weld on convertors will cause in range failures. I have had to pull them off and go factory, to keep the service eng. soon light off. In todays world, black tape over the light is not always a good idea.