I recently bought my first Ex about 2 months ago. When I first got it there was a little lag time, or hesitation sometimes taking off from a stop. It also idled a little low for my taste and shuttered from time to time. It is a 2004, 4.6, with the "drive by wire" throttle. It was doing this when I test drove it, but I got this vehicle far below bluebook so I felt I could spend a little money on it if needed to get it up to par.
About 2 weeks ago I started to notice it taking a turn for the worse. It would die often in the mornings, and some times during the day, It was idleing around 3-400 RPM's ( just barely even running). The lag/hesitation between the time I pressed the accelerator and when it actually started to take off was brutal. A good 3 seconds some times. Then when it did finaly WAKE UP it was like I had it half way to the floor. A real pain to drive this way. When I would shift from park into gear it would clunk really hard. Harder in Reverse than in Drive. It was even shifting throughout the gears a little funny.
I started doing tons of research online and trying to narrow down what could be causing it. The only code the computer threw out was the Low Idle Code, but that was it. Once I reset the computer it never threw the code again even though it was still running like crap.
I decided the truck needed a tune up anyway and that should help. So I changed, Air filter, Fuel Filter, Oil change and filter, Cleaned the injectors, changed plugs, tested all the coil packs, Replaced PCV valve, TP Sensor, and checked for vacume leaks. After all that it had way more pep, but still wouldnt Idle right and had the hesitation.
I finaly decided to pull the entire throttle body and just LOOK at it. Once I got it off I noticed all the gunk and crap that was completly cutting off air supply when the throttle plate was in idle position.( assume this is because when I changed the Air Filter I noticed they had a K&N Filter and used WAY too much oil in the filter, I just use a dry filter with a little oil around the seal and change it with every oil change.) I gently cleaned every bit of the buildup out of the entire throttle body with WD-40 and some rags. This took about an hr in itself. Carb cleaner would have taking about 10 mins but was told not to use it on this throttle body.(not sure why?) Put it all back together and it runs like a new truck!
Idles around 750RPM's and no hesitation. No more clunking into gear going from park. Every bad symtom I had is gone. The only reason I posted this long thread was because I have been seeing many complaints with the same issues I was having, and everybody was just buying new parts and nothing was getting fixed. So I think a good cleaning would do the trick in many cases.
Sorry for such a long post!
Ike
