It seems like when I keep my RPMs high, mileage goes down. Especially at 3500 rpms (no OD), I get 23 mpg vs. 29 mpg at lower RPMs.

 

Yup.... It takes more fuel to spin the engine faster. Try the exact opposite - shift @ 1500 rpm.

 

Keep the revs in the mid-2000 range!

Anything outside of that either lugs the engine (too low on the revs) or is a waste of revs for whatever gears you are in...like 3500 w/out overdrive.

 

It is a 3-speed auto. Yeah, I am aware that the ideal range of RPMs is about 2500. At these rpms, I am going about 50. I get decent mileage up to about 3,000 rpms but higher than that and it drastically declines. It is a Topaz with 2.3L auto, and 3.23 axle standard for '87.

For my 7.5, the best mileage would be achieved at 2200 rpms but then that means going 45mph. It has 4.10 axle.

Also, it seems the higher the rpms, the more oil it burns.

 

i just gave my 88 topaz 2.3L auto to my brother. it only had 50k mikes on it but it just cant handle the highway speeds. i upgraded to a 92 ranger with the same 2.3L engine, but a 5spd manual. u wouldn't believe the difference when you have overdrive. i get about 2mpg better with the ranger. my recommendation: use the 3spd auto for local driving. if you do alot of highway, get something with overdrive -Jesse

 

I just drove on interstate highway the other day, mostly at 3500 rpms. It is possible, but your MPG goes to 23, it is noisy and probably shorters the engine life.
I have a vehicle with 5.7L in it, but then it is only gets 20 mpg.

It will go pretty fast, but acceleration is abysmal. 0-60 = yes.

 

u get 20mpg with a 5.7L holy crap the topaz will handle the highway. the 2.3 is a strong engine. it lasts about 250k in a manual and maybe 150 in an auto (these are just approximations). as long as u can deal with the noice 3500 rpms makes i say go for it. it could easily last you years.

 

Some people on tempotopaz.com claim that they have gotten as high as 250,000 miles on T/T. The engine is fine, but it is usually other stuff which falls apart around it.

 

its all in how you drive
In my ranger i average 24/25 mpg. On the highway I can get 27+. I lost the exact figures but the average was cumulative over nearly 3500 miles and multiple tanks to eliminate as much error as possible. I drive about 70 on the highway, tailgate up.

 

This is not surprising, some report 30+ with manual tranny, wish I had one.

 

i dont know how thats possible when you're revving 2500 at 65mph. interesting.

 

If I got got 30 mpg with my 2.3L 5 speed I wouldn't feel so bad about it's guttless nature. 50mph, approx 28 mpg. Go 75mph, approx 20 mpg. Go 85mph, only with a tail wind (no hills in SWF to go down)

 

i haven't had my truck long enough to calculate highway miles but that sounds about right from results of city driving. i agree 100% with you.
since i'm having to rev at least 1500rpms for first anyways, i'm thinking about increasing my gear ratios, something to the effect of getting about 1500 rpms at 65-70mph. i have to look into the cost and mechanics (hopefully something i can do myself on a weekend).

 

if you have the 2.3 you wont have enough power to go 65 mph at 1500 rpm's, unless you drive off a cliff or something. in theory it would work, if there was no air/wind resistance. at 1500 rpm's you probably only have like 50 horses(w/the 2.3), because you are so far from your peak power, which is a whoping 100 or so houses. at 65 mph it would take just about 50 hp to overcome the wind. now add friction from all the moving parts and tires to slow you down and you get the idea. i'd keep it above 2000 rpm's when over 60, you'll save gas(engine wont have to struggle while ur injecters just shoot large amounts of gas in) -jesse

 

A friend of mine just bought a tempo with 310,000 miles from the original owner.