I have a 2019 3.5 EcoBoost with about 29k miles. This started a few weeks ago. The truck feels like it's lost some of it's oomph, the power feels week. And the engine doesn't feel smooth - it feels kind of sputtering, especially around 30-35 mph. Engine feels better when I'm on the gas and accelerating, but still weak. I also get a pronounced cutout/jerk-back-to-life within the first minute of driving first thing in the morning. There is NO CEL or CODE.

I'm no good with diagnosing engines. My guess is it's running lean, but wouldn't that cause a CEL? Maybe it's lean, but not lean ENOUGH to trigger the CEL? Anyway, I cleaned the MAF sensors myself, but nothing changed.

I took it to my local shop (non-Ford, because the dealer service depts near me are not very responsive). They said they drove it and didn't notice anything wrong. My guess is they don't know what it's SUPPOSED to feel like so they don't recognize that the power is low. I asked them to let it sit and try it again.

What could this be? If they shop still says they see nothing wrong, what should I ask them to check/do?

 

29K miles yikes but one item that comes to mind is plugs. Motorcraft plugs and the right gap.

 

OP, what did you use to check for DTCs? Often a high end diagnostic scan tool or FORScan will detect codes that simple readers don't see.

 

Nothing - there is no check engine light so I didn't use a scanner. Is it possible there are codes without the CEL? (I assume the shop would have done this though.)

 

There are many, many DTCs that do not illuminate the CEL. Don't assume anything.

 

Yes - not all codes trigger the Malfunction Indicator Light (MIL) [aka Check Engine Light]. As 52merc said, you will need to use FORScan or a high-end diagnostic scan tool to check for all possible codes.

Regarding your shop (or anyone diagnosing your truck), I would not assume anything. I would ask what they did and what scan tool they used.

 

Someone on Reddit said they had similar symptoms and the problem ended up being the fuel pump. I read somewhere that it can wear out if you run the tank low frequently (which unfortunately I do - bad habit). Is that something that would produce a code?

Talked to the shop again, and they WERE able to produce the issue. Said the mechanic suspects something transmission related and wants to let it sit overnight and run some diagnostics in the morning. It feels more like a fuel system issue than transmission, but who am I to tell him how to do his job? He can check what he wants as long as it gets fixed in the end. I mentioned the fuel pump, and the manager said the mechanic would check it.

 

Whats the possibilities that your vehicle is still under Ford's 36 month /36,000 mile warranty, 60,000 mile power train or some of the extended smog warranty?

 

Hopefully it's still under the Ford warranty. I'm under the mileage, but right around the 36 month mark. I'm the 2nd owner, so I don't know when the 1st owner took delivery. I do have a 3rd party extended warranty to 60 months/100k, but it would be nice if I can go through Ford.

The shop said it appears that the fuel system is fine, but the transmission is slipping. They recommended I take it to Ford, so I took it there this afternoon. They'll confirm the transmission diagnosis, and I asked them to check the fuel system too. I went to a dealer a little farther from home that I've used before, and they seemed like they were competent and conscientous.

 

You can quickly check your vehicle's Ford warranty info by entering its VIN into this Ford website: https://www.ford.com/support/warranty/