I just installed my new AEM CAI and put in the Superchips performance tune. MAN!!! It really woke the truck up. The one thing I am still curious about though is the loss of power I have had over the years. I have a 2003 QC HEMI and when it was new, after disconnecting the TCM, it would really smoke them down and had plenty of power. Over two years later and 82,000 miles, the truck seemed to lose a lot of power and I couldn't spin a tire even when trying to brake torque it. The engine would just bog and acceleration was poor. Also, gas mileage when new was in the upper teens and decreased to low teens. After installing the new program and CAI a lot of the power and mileage came back, but not like it was.
What makes an engine lose power over time, and is there anything else I can do to get it back. 80% of the miles on the truck are highway miles driving 74 miles one way to work every day. I know when stuff gets old it slows down, but what is the main cause of this? Rings, valves, head work, more clearances on the worn parts, and carbon build up are my first guesses. Is there anything I am missing?

 

I'm no mechanic, but, maybe your cats are getting clogged and restricting exhaust flow?

Mike

 

Have you done the basic maint. For having 82,000 miles, if you havent already, change plugs and wires. Flush out old fluids.

 

Yeah, I am a freak when it comes to maintenance on my vehicles! I do need to have the tranny flushed again and probably the coolant (both done at 50,000), but everything else is fresh. I forgot to mention when I installed the CAI there was a lot of carbon and oil built up inside the throttle body from the EGR tube, and I noticed the truck is starting to smoke on cold mornings for the first few minutes before it warms up. I think I am getting more than normal blow by from my rings. The only other thing I can think of it being is the valve seats, but I am not sure how the internals of the HEMI head is configurated.