My '07 Supercrew with the 4.6 and performance chip has felt even slower than normal lately. It has 90,000 miles on it and I've done the maintenance all along. It's almost to the point where I want to dump the truck for something different. It's almost unliveable. What could be causing this? Is there some maintenance I need to do or what?

 

It must be really hot where you live, same here. High temperatures make for really good fuel mileage, but terrible power and general engine performance.

 

Have you tried the use of any kind of fuel injector cleaner? Opinions around here are mixed on the subject, but I find that Techron fuel injector cleaner does a great job. It has solved my light knocking problem that started when the truck rolled off the lot.

Have you ever changed your fuel filter? If not, it would probably be wise to do so since you are approaching 100,000. I learned the hard way myself... Didn't change it until my fuel pump went bad at 100,000 miles. Needless to say I'll be doing it much more often now.

Have you been religious with the maintenance schedule and used motocraft oil, filters, and other parts? Has your check engine light came on? Notice anything else unusual such as noises, hesitation, stalling?

The more specific you are the better. I'm not a mechanic myself but if you answer the above questions, I'm sure it will make it easier on the people who are. I hope I helped you and good luck!

 

A change of the front O2 sensors brought my 4.6 back to life. I was having the same issue with mine- seemed like the engine was lazy. Use only the Motorcraft sensors. Most after market sensors are wide band where the Motorcrafts are a narrow band. At 90,000 miles, they're due anyway. Change the fuel filter, PCV and spark plugs with M/C only, use a good injector cleaner like Ford approved Techron and she should be ready to go.

 

Do you have an aftermarket intake with an open filter?

 

I have a stock intake and I've done all my maintenance all along including the fuel filter.