Hi, I posted this in the new members forum and thought that posting here would get a response. When your new you don't always get it right the first time.
Hello all,
I have a Triton V8 4.6L with 114K miles that has been running great until the past couple of weeks. When I am cruising about 50-55 and try to accelerate the truck hesitates and eventually after 3-4 hesitations will reach the 70MPH I wanted to get to and continues to run fine. There are no problems accelerating from 0-55.

Nothing has been done recently, I need to replace plugs and wires as everything is still original. But, this problem seems to be more than plugs and wires. Air filter has about 5k miles on it and is relatively clean.

I've seen posts on the web related to problems w/ IMRC runners.

Any help would be appreciated.

 

I would start with the plugs as you said. That's a lot of miles on a set of plugs, and could be causing the problem. I would also run a fuel injector cleaner in the tank at the same time to eliminate dirty fuel injectors as well.

Give it a good tune-up and keep us posted.

 

Thanks for the info. I changed the plugs and it looks like that helped, if not corrected the problem altogether. A new tank of gas seemed to help as the problem started going away after filling up and before I changed the plugs. Ever since these two actions I have not experienced any more problems.