Trouble maintaining highway speeds...

Hello all, new to the forum and Tundra ownership. Hoping some of you can shed some light on an issue I have had with my new to me Tundra. Mainly, it’s just a lack of all around power available. It is somewhat apparent at city speeds, but more pronounced when I get her on the highway. She seems to be turning about 2300 rpm at 70, and at almost any rise in the roadway surface she has to downshift just to keep at speed. I went the first gen tundra route because of the v8 so I could still pull my Polaris ranger, but I don’t think she could handle getting it down the highway as is. My question, is this normal behavior? If not, where should I be looking to solve the issue? Are the over sized tires the problem? When I let off the gas it feels like I am driving in sand and she starts pulling me slower and slower, there is no coasting. Any help would be appreciated.

 

Do a shake down check of fluids levels in transmission and rear diff. Check rear brake shoes possibly sticking.

 

First thing I did was completely rebuild the drums. Nothing changed, but it does stop great now. I will do a fluids check on those next.

 

My grandfather had a similar issue on his GMT-400. I think his resolution was to replace the fan clutch but I'm not sure how he determined that was the problem or if Tundras tend to have those go as they age.

 

Funny you say that. I have noticed the fan spooling up constantly and sapping 75% of engine power regularly. I haven’t thought much of it considering it’s been 100+ F the last few weeks. It has made me want to ditch the mechanical fan altogether and retrofit for electrical.

 

Possibility of the catalytic converter plugging up comes to my mind. Had a car in HS with that problem, but it had a noticeable power drop at all times - not just at hwy speeds.

 

I'm along the same lines of dragging brakes or clogged cats. Do you have any kind of IR scanner or temp gun? It can check both brakes and cats.

 

I have an ir camera. I’ll check the cats. Pretty much positive it’s not brakes. I haven’t smelled them at all and have taken it on a 1100 mile road trip. what am I looking for when I inspect for clogged cats?

 

There'll be a temp difference somewhere. I don't remember off hand what it is, but I think the cats will be hotter than they should. Also, my rear brakes were dragging bad, and I never smelt them. They got pretty damn hot though.

 

I’ll look in on them to be safer than sorry. Any idea what temp range the cats should be in normally? I’m coming from a diesel which run really high egt’s

 

I think you check before and after the cat.

Same = bad
Plus temp on exit = good.

 

This got my attention, I think this same issue is happening on one of my tundras. Is your truck all stock? No lift, big tires etc?

 

Hmm interesting, during 100 degree weather, if my truck idles, say in a drive through, I get a pretty audible fan roar and loss of power until I get the truck moving again at good speed. I thought about replacing the fan clutch and possibly the radiator. Does your truck do anything like I’ve described?

 

Normal, that's how it should work. Clutch locks up when it heats up and unlocks when the temp drops.