Scotty thanks for your help in advance! I’m a veteran from East Tennessee, welcome to the greatest state in the land of the free! My brother in law has a 2008 F150 crew cab 4x4 with a 5.4 triton and automatic trans. It was running fine then he got it serviced and “tuned up” (including spark plugs replaced) at the local dealership.
Now when the engine is at operating temperature and he enters stop/go traffic and is pulling out from a stop (foot on the gas) the motor will rev up (high enough for it to vibrate) but the truck does not accelerate immediatly. It does it intermittently and the dealership says they can’t find anything wrong but the truck still does it, help!
Definitely take it back and make them fix it.
Sounds like it got "Tuned Down", not up. I would take it back and demand that it be properly fixed or get your money back.
Yes, I agree but if we can't deal with the dealership what could the issue be?
Why can't you deal with the dealership? I'm sorry, but if I just had work done at a dealer I'm not troubleshooting anything related to that work myself. I'm taking it back and either they make it right, or they give me my money back.
In addition to what @mod_man said, dealerships usually give you a limited time warranty on their work, post service. You should have no trouble getting them to fix it right, or asking for all your money back.