So now I need to know what I should do in terms to boost HP n MPG ... cause as we all know more HP equals more mpg to a certain extent as long as We are nice with it.. so what should I do to get as close to equality in both as possible? Just looking at it as a 15 year old truck with 128k n nothing Don't to it in say... The last 20k
What you can do to get better mileage: remove the 285/75R16's currently installed, and install a lighter tire and wheel combination. The stock tire should be a LT245/75R16.
If you don't actually use your truck to haul heavy loads and tow frequently, you may get away with a lighter tire. I am not sure if a P metric 245/75R16 would be rated heavy enough for a CCSB though, at 2271 lb rating.
If it is, then a Michelin LTX M/S2 would be my choice @ 34 pounds each. Stock steel wheels weigh 34 pounds each. If you had a 285/75/16 BFG All-terrain, they weigh 56 pounds each.
Shaving 22 pounds off each corner will do wonders for acceleration, braking and ride. Combine that with a set of aluminum wheels, and you could be even lighter, coming in at around 18-20 pounds each for a light weight aluminum wheel. With an aluminum 16" wheel and a set of lighter tires, you could be even as much as 36 pounds lighter on each corner.
The stock 8600 GVW y-pipe and air box are different from the lighter models, at least when I compared the 1997 K1500 305 airbox to a 1998 K2500 350 8600GVW. The factory 8600GVW y pipe flows better, and the air filter box is less restrictive. ( 8600 is a single layer, the lighter one has baffles and resonator tubes with a dual layer )
Change out the plugs, install a fresh set of Delco Iridiums if you haven't already, and a fresh cap and rotor. If you have a compression tester, it would be wise to pull a compression test while you have the plugs out.
I would go to a pair of higher flowing mufflers off of the factory Y-pipe instead of the single muffler and use dual tail pipes.
If money allowed, a set of headers would be next on my list, however you need to find ones that have a fitting for the EGR tube.
A lighter weight synthetic oil in the engine can net a very slight improvement in mileage, there is a reason that newer vehicles are using these. If you don't have a G80, then you could use a thinner synthetic gear oil in the rear axle as well.
Also, if you are concerned about economy, remove the lift, drop it back down closer to the road, ensure the factory air dam is installed on the bottom of the bumper, remove any towing mirrors and bug deflectors and ensure the factory 2" nose down rake is set.
Check the tires for proper pressure, check all the front end components for slack, and do an alignment. If all of the above doesn't pick up the mileage, nothing will.
