Problem taking hills at high speed

I have a 2013 Double Cab Off Road with manual transmission.

I'm on a nationwide road trip right now and I've noticed that sometimes, when going up a hill, I'll lose speed and the cruise control will cut off.

---The facts---

I'll have it set to 70/75/80 MPH usually. Then I come up to a big hill and I'll start slowing down. After I lose about 10 MPH the cruise control turns off.

I notice that my RPMs typically don't move though. They just stay at 2.5K and hover there. I can push gas all I want and it won't go above 2.5K RPMs.

My truck will, in some conditions, go above 2.5K RPMs and I've had it up to 100 MPH yesterday, so I know it's capable.

Also, the bed is full of stuff, but I'm not over any limits and I'm not towing anything.

---My theory---

I'm thinking this has to do with air density. It seems that this happens more often when it's a steep hill at an already high elevation. Something in the computer knows that adding more fuel isn't going to help when what it needs is more air.

So my question is, assuming my theory is correct, how can I add more air? Bigger intake? Supercharger? Actual functioning hood scoop?

Let me know what you think.

Thanks.

 

I'm guessing the hills you negotiate at home are not as steep as what you've encountered on this road trip?

 

When I moved to DC from AL I towed a Uhaul through the appalachain mountains without any issues whatsoever. The mountains out west (CO, UT, etc) are proving more difficult for the truck by itself.

 

Cruise control with an automatic transmission has the luxury of downshifting when it needs more power to maintain set speed. In a manual, obviously the downshift must be provided by you.

Loaded truck going up steep hills or mountains will struggle when in high gears. You can push the gas all you want but what it needs is a shift to lower gear.

Rocky mts are a bitch!

 

There is not enough info to condemn anything here. First and foremost, do you have armor? If the answer is yes then the issue is the extra weight is causing your engine to now be gutless.

Supercharger is the only solution. I'm being serious actually. Even 200lbs of extra armor weight is enough to load you down to the point of the truck running out of steam up hills. 236HP is simply not enough balls to keep these trucks climbing for what they weigh.

 

With a manual trans, you’ve gotta downshift. Is this your first manual transmission? (Serious question) Any time the engine starts lugging, you’re in too high of a gear. Turbos and superchargers aren’t as prone to this. (Especially turbos- more load=more boost).

Edit- I did a cross country trip in my ‘07 DCSB 6MT, encountered the same issues over the Rockies. Hell, ANY long steep grade where the tach falls below 2700-2800 RPM warranted a downshift. Sometimes the wind alone in Utah forced me to drop it into fifth gear on the highway. It’s the nature of the beast. You’re driving vehicle with the aerodynamics of a brick with not enough power.

Edit2- I learned to upshift from 1st through 6th with no clutch on my trip. Kinda fun, but wasn’t fun for the reason I had to learn.

 

Your engine loses about 3% power for every 1000' of elevation. When you get to 5000' you'll notice a difference, above 10,000 and you'll notice a big difference. Slow down, downshift. Your engine needs about 3500-4000 RPM's to generate max power.

Back in the 1970's 3/4 ton trucks were getting along just fine with 165-175 HP engines. It's about gearing and hitting the right rpm's

 

Lots of those trucks had more torque, no? The straight sixes had generally a 3-on-the-tree and 240torque. I’d imagine the v8 had more torque.

 

You have a manual transmission...

The engine doesn't have enough power to keep you at your set speed in cruise control (in 6th gear). Downshift to 5th, and if necessary 4th to keep RPM's up. The Tacoma is a driving brick, not a rocket ship. Slow down to 65-70 and you shouldn't have any issues maintaining speed up inclines. I almost never keep my CC on when approaching inclines due the the high chance I'll have to downshift.

I'd hate/love to see your MPG's at 70/75/80 MPH, especially if you're trying to maintain that up an incline. Stop at a gas station every 200-250 miles?

 

Before I asked this question I could've sworn that I had tried downshifting and was still having issues, but since reading through this and completing my trip it seems that I somehow forgot about downshifting. Stupid on my part.

No armor installed yet, for the person that asked that.

I get between 15-20 MPG depending on how much construction I hit. I would stop every 3/4 of a tank which puts me at about 230 miles on average.

Thanks for the inputs.

 

When the vehicle is in one of the following conditions, the ECM deactivates the cruise control (the cruise control can be reset).

• Actual vehicle speed is below the lower vehicle speed limit (the set vehicle speed is retained).
• Actual vehicle speed decreases by 10 mph (16 km/h) from the set vehicle speed (the set vehicle speed is cleared)



Yep - Time to downshift and hammer down the throttle

 

This, use a lower gear. These trucks need revs for power. Your truck can make a certain amount of power at each RPM, yours maxed out and kicked out the CC. With your manual transmission once the CC maxes the power output the only thing left to happen is speed and revs dropping along with power.

 

It happens. Down shift when it does. I think if you drop 10 mph it will cut out

 

I can't even hit 5th in my old 2.7 going up the 6% grade where I live. I get to 4th gear, wind it up to 55 mph, and enjoy the scenery.

I don't have cruise control, it's like they knew it would suck so left it out. Could have given me a tach though. It's just weird to produce a manual vehicle without it.

 

This is spot on. What you are experiencing is normal with cruise control and a manual tranny. Cruise control is really meant to be used on the level highway or straight highways with some minor grades. Even without cruise control if you go up a steep hill your truck will slow down if you don’t down shift. Just use your cruise control on level highways or mostly level highways. Use your stick like you are suppose to.

 

Drop it down to 4th. Hit resume.

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I have driven through the Appalachian mountains in my 4 cyl 5 speed with a good size load in the bed. It was not uncommon for me to be in 4th gear to maintain 70 in the mountains(I'm sure our transmissions are going to have different outputs in different gears obviously) I imagine you need to be in a lower gear.