I realize that the following information may not be as detailed as some would like, but:


My 2005 QC 4x4 4.7 (non HO) with approx 55,000 miles, has developed a mind of it's own!

I am experiencing noticeable changes in engine RPM's, throttle response, and more harsh shifting points, with and without direct foot-to-pedal input. This is very frustrating! Just coasting, where speed limits/grade/traffic/etc permit, I can hear and feel the engine revving or slugging, randomly. It's not even remotely drastic enough to cause a collision, but something is definitely wrong.

Points of interest:

A> This problem has been present for approximately 1(one) month, with no apparent cause.

B> I have been using Royal Purple for over a year, with more than adequate oil changes (by frequency, mileage, and driving conditions).

C> I use the same 87octane gas from the same stations(QT-KCMO), that I have been using for over 2 years.

D> My driving habits (very conservative) have not changed.

E> I changed to properly gapped Autolite's (3923's I think) about 6 months ago, with no initial or noticeable changes in performance/mileage. (pro or con)

F> I have made no other mod's or changes.

G> I am not covered under any warranties or maintenance programs.

WTF is wrong with my truck?
How do I fix it?

 

Are you stuck in Tow/Haul mode? Haha. When was the last time you flushed the transmission and changed the filter, or verfied the amount of fluid in the transmission? When was the last time you disconnected the battery?

 

what he said, also check your egr valve. it might be stuck and not properly working. also if you bought truck new you still have a warrenty up to 70000 miles. might even be a simple cracked vaccum hose