Question about interstate travel

Hey, the Taco is my first car, and the fact that it is a manual means it is my first manual. I apologize now for the lack of correct terminology. When travelling up the hill on an interstate and the truck either starts to deccelerate or will only hold its speed. Now here is my question: What is the difference between...

....holding the pedal 3/4 of the way down, maintaining ~2800rpm and maintaining 70mph

...and flooring the pedal, maintaining ~2800rpm and maintaining 70mph.


This question is pure curiosity on my part. sometimes i notice a different tone/vibration when it is floored

 

that different tone is your engine struggling to maintain power going up the hill while your flooring it.


Down Shift! it will be less stress on the engine

 

However, sometimes if I let off of the accelerator a little bit, the vibration goes away and the trucks performs the same/better

 

so what is the difference between when it is performing the exact same, but vibrating vs. not vibrating. Is that just it not being able to respond to the pedal being depressed further

 

When you floor the pedal- It knows you want to go faster- So it adds fuel and tries...but at the grade and speed you are at- The engine/transmission CAN'T physically move any faster but it tries...causing the vibs.
When you have the pedal 3/4 of the way down you are providing it enuf fuel to maintain, but not try to accelerate.
The downshift is vital- It'll give you the extra kick you need for those troublesome grades.

 

Ya trust me i know how and when to downshift and all, this was just a question from my curiosity. I was wondering because the harder i press the pedal in this situation, the more vibes i get, but the RPMs donot cvhange so I was just curious whats going on in the engine

 

Fair enuf- Not knocks on your driving skills- Just a comment in general.

 

haha thanks all for the info! I'm still just a little curious why exactly the vibes occur with no change in rpms.

Is it actually putting more fuel in the engine and it just can't handle it?

 

YAY my curiosity is no more! Thanks a bunch guys!

 

A little side note, typical interstates wont go steeper than a 7% grade. Due our 6spd shorter gearing, unless your towing, you'll most likely never need to downshift on an interstate (just have to push in the pedal a little more).

Btw @ 70mph you're at 2500 rpm (6th). Not going over 70 will really help on gas and hey, no worries about speeding tickets. Good to see you went w/ the manual.

EDIT: Scratch my numbers...was talking 4.0 w/ 6spd. I now see you have the 2.7 w/ a 5spd.

 

haha ya, this interstate (I81) runs through the Appalachian mountains of VA. They aren't steep hills but I still have issues if I dont keep my speed up. On the flip side I save some gas in neutral rollin back down those hills