2015 F150 5.0 80,000 miles. Starts fine in the mornings. This summer I notice when I start at lunch/in evening, it spins over much longer than in the morning before it starts. Almost like it is vapor locked. I also notice like dead spots in the acceleration at times, usually in the low RPM range. I know I am getting close to time for plugs (100k), but wondered if anyone else has seen similar on their trucks?

 

How much longer does it crank VS in the morning? It seems like a fuel mixture issue. Any codes and I mean have you connected a scan tool or ForScan to check for soft codes? Try running a can or two of Seafoam through it too and see if that doesn't help. Oh, and go "road hone" it like an old mechanic used to tell me. The first time he said that to me (I was an apprentice mechanic at a Chevy/Toyota dealer), I looked at him sideways and asked what that meant and he said go drive the **** out out of it!

 

Pull a plug.

No seafoam for me..... maybe a bottle of Techron if you haven't been using Top Tier Fuel.

Nothing wrong with a quick "Italian Tune Up"

 

I agree with idrive, no seafoam but let him stretch his legs. "Babying" an engine can cause more problems than pushing it. A co-worker I had a former job had a fully loaded Trans-Am that had similar problems as yours with hard starting and rough running. He said after a few trips to get it fixed at the dealer the service manager asked him if he had a teenage son. When he asked why the manager said if you let him drive it I promise you'll never have these problems again. From then on he did a few foot to the floor runs and let the speedo get into the triple digits occasionally and never had that problem again.

 

Second to last payment on your truck means you are almost done!!!! You'll have cash to fix any issues that come up. Then, after you fix them, you'll have the cash that went to payments.