Your talking about the muffler being sensitive someone put a little muffler
on this thing (like on on a car) it has the 2.25 outlet and inlets but the
stock one is like huge compared to the one on the truck now.

I agree with Bruce, the exhaust system needs work. If you know a good
pipebender at a local muffler shop, you can gain some power for a
reasonable price. Many years ago I put headers and turbo mufflers on
my Monte Carlo (355ci/325hp) and had a complete dual exhaust system
fabricated to fit the car. The gain was amazing. But, to be practical
I would recommend a good exhaust system with a stubby turbo muffler.
Don't even consider a glasspack! A little exhaust sound is ok but blat
blat is very uncool.

Your cheapest horsepower (and gas mileage) gain will come from a good
tuneup with stock spark plugs and new gas and air filters.

You can replace the fan with fiberglass or electric.

Synthetic oil will also help.

You can get into exotic parts, but it gets really expensive

My 4.0 has enough power for me and my HO 4.0 (like yours) has more
than enough power for my needs.

I had considered more horsepower for my commuter car a few years ago.
All I wanted was better 50-70mph passing power. I did most of the
above and wanted a little more. I came to the conclusion that an
electric turbocharger was the right way to go. I suggest you look into
this and decide if you want to spend the money for a little more
power.

Just remember that "cheap horsepower" is an oxymoron.

Merrill

Why do you call it a truck ??

Yeah and stick a rubber hose into the throttle body, hold the can upright
and spray it!

Dream on. The push button switch is usually on the shift lever, where
you add whatever HP you wanted by the size of the kit's buttons, usually a
hundred horsepower, so you won't be doing wheelies, just maybe making that
hill you previously stalled out on.
       God Bless America, Bill 0|||||||0
mailto:LWHughes3rd@aol.com http://www.billhughes.com/

I installed a boost-a-pump that increases the fuel pressure to 70 psi
and a pressure regulator on the fuel rail that's stonger than stock.

If it wasn't there before then suspect dirty fuel filter or
clogged injectors.  Also poor spark will cause problems.
If all else is fine have him try one range cooler on the plugs.
And don't use platinum or splitfire as they cary too much heat
and can cause detination problems.

If it was always there then he needs to retard the timing a bit
and increase fuel flow with either larger injectors or a higher
pressure pump/regulator.  Some systems use a seperate injector.