Loss of power/ Regear?

I noticed in a recent 3 hour road trip that while going up hills, it was very hard to maintain my speed without flooring it. It mostly only happened around 70-75 mph. I'm running 265/75/16. Any ideas?

 

shifting correctly?
4 cyl or V6?

keeping up on maintenance?

 

It shifts just fine! 3.4L V6. Id o everything myself and have babied it for a long time now

 

I run the same size tire with the same engine, I noticed 0 loss of power from stock.

Sounds to me you might need a tune up, regardless of babying the truck thing will wear out and get dirty.

I am hard as hell on mine and I have 200k miles no major issues but I maintain it like crazy with detailed notes.

 

Given the factor of three hours in one direction, that would be a total a six total hours. Most of us in normal day to day operation would be used to a typical 1-2 hour commute and thus notice no real change in our vehicle under stress via terrain change on the roads.

However, not knowing where you live, elevation at three hours away could change drastically for you and you would notice a significant struggle in your engine.

 

I'm running two steel bumpers but I didn't think that would make too much of a difference. Spark plugs were done almost only 2 months ago, but I didn't do the wires. Only other mod is a magnaflow 18" just put on

 

Ok so I dont know your mileage but the wires should be replaced every 100k at the minimum.
What was your average mpg?
Have you replaced your O2 sensors?
Cleaned your MAF sensor and Throttle body butterfly?
Replaced your air filter? they only are good for 10k-20k at best.
any issues with running hot?
Have you replaced your front, rear, transfercase, transmission gear oil?

These can all play a part in power loss.

 

He only said he lost power on hills. Not loss of power all together.

 

auto or manual ?

265's are only slightly taller then the factory size.
so unless these hills included extreme elevation changes...
It's likely a tune up issue.

What is your factory axle ratio ? Code ?
4.10 shouldn't be too bad...
but a taller ratio would likely suck.

btw... if those hills include substantial elevation changes...
then that by itself will reduce engine power.

I run 4.88's on mine... (5vze)
I can roll 5th gear up most any incline.
Even pulled a trailer up to Moab...
and the elevation increase from California was big...
But I still managed 5th gear going up.

Realize lower gearing improves torque...
and can compensate for taller tires.
but doesn't increase the engine's power output.

Only way to get more real useable horse power...
is installing a supercharger.

 

doing 70-75 in 5th gear up hill without flooring it will slow down.. this feels like a troll bait thread or math question.

Hills or not I asked legit questions regarding upkeep.

 

Lol, I don't think its a troll bait thread. I just think the OP has traveled outside of the norm and got concerned when his truck struggled. Your questions are awesome and warranted, but his question was specifically tailored to "up hill".

 

Maintenance relative to this recently:
Magnaflow 18" muffler.
Plugs changed maybe 5k ago.
Read diff oil changed with 80-w90 3 weeks ago.
MAF cleaned with MAF cleaner maybe 3 months ago.
Also almost new O2 sensors.

Was thinking maybe cats?

I noticed it most uphill but I must admit it has been noticeably sluggish compared to when I bought it 20k ago. It has 165k now

 

I think its relative perception honestly. Sure, the cats may be clogged. The engine is a bit worn. Your maintenance is well kept. I believe its just throughout your trip the "perception" was your truck was not operating to your standards, when in relativity it was.

I'm speaking from my experience in driving long distances. I used to live in Oklahoma and drive to Georgia twice a year. Thats 16 hours in one direction and i've done it in one sitting, several times. I had an awesome full size GMC truck with a V-8 and noticed struggles just like you did, but not all the time did I notice! I also owned a brand new Maxima in 2010 and the same thing. That car would, and still does, fly. But the longer your drive and the further you get away from the norm the more likely you are to notice a "problem" when in actuality there isn't a problem.

I own and RC 4x4 manual with the 2.7l. Its sluggish to me since i've bought it. However, still gets me to work on time and I can still pull my bass boat down the highway just fine. I go off road around the farm and the truck does exactly what its always done. I become inferior when I see a big ole' Dodge 3500 Cummins diesel pulling a deep sea fishing boat come fly by my little Taco doing 90 mph. He doesn't have a struggle in the world on the highway...but me...i'm down shifting to fourth uphill and tugging right along loving life!

 

Do you have records of the timing belt and water pump replaced? That should have been done at 120k miles no later.

Also power loss is more noticeable when under load like a hill versus cruising around town.

Stupid little things like tire pressure are overlooked and can cause resistant as well but very little.

Sounds like you had a lot of replaced parts, the gear oil should have been 75w/90 all around, I change mine every 30k and the rear diff every 15k.

 

TacoMeElmo, I have replaced a lot just due to peace of mind haha. I'm paranoid when it comes to my truck and have modded a lot of things but haven't touched the engine or chassis much and I only use stock parts when it comes to work done. My timing belt was done at 95k approximately at the dealer according to records. I suppose I'll give it a tune up but am unfamiliar with what a full tune up with these trucks entails. Mine is an 02' PreRunner. Any help is much appreciated! I am not sure if the previous owner ever once changed the rear diff oil, so I did that on my own very recently.

Also, my owner's manual says that I should be using 80-90 for my gear oil?

 

I have a 4x4 5 speed so my truck takes different gear oil than your in a few spots anyways I think.

I also have 1 more gear than you so maybe the truck is having auto trans issues as well. they need to be serviced like a manual with new parts too overtime.

Also depends on if you use the OD button.

 

I never use my OD button.

You believe that it might be auto trans issues?

 

In pretty much the same predicament. I though for SURE it was my cats. Just had a whole new system installed with a mag high flow. Almost no change. Do feel a bit more power now, but she's still pretty sluggish. Especially on windy days and up hills. Have tried the usual suspects like cleaning maf and tune up.. I'm stumped. I think I'm gonna break down and get at least a new a/f sensor as well as maf sensor and see what happens.