[sn95 mustang kg]

Is that natural or is there a problem? I dont remember it running that low....

[mcqueen]

What gear ratio are you running? With 4.10's I'm running something like 2500 RPM in 5th gear at 70mpg.

[Assassin_Dan]

Originally Posted by mcqueen What gear ratio are you running? With 4.10's I'm running something like 2500 RPM in 5th gear at 70mpg.

I wish I got 70 mpg

[mcqueen]

Originally Posted by Assassin_Dan I wish I got 70 mpg

I'm just that cool

[sn95 mustang kg]

I dont know what gears i have in it, i just cant remember if it always ran like that

[wolfeman04]

i believe mine runs at about 2000 at 70 with stock gears

[blownandstroked]

wow u must have some dessert gears there

[motorhead6776]

standard or auto? my guess is that its would be an auto and theres something wrong with it.

[99 BLUE V6]

Do you have taller than stock rear tires?

[JTs03v6]

Nothing wrong. It's just that your stock gearing is pretty low. 2.73's I believe.
I woulkd look into swaping them out.

All 99+ v6's come with 3.27's and I have a set that come out of mine if your interested.

[sn95 mustang kg]

It's standard.
No just regular size tire.
If it's a problem I've got my rear end out of my 95

[Assassin_Dan]

I remember mine ran pretty darn low before I got my gears.

[9986paulk]

If I'm not mistaken that would require a top gear ratio of ~.5 and lower than 2.73s...I think something's wrong. It would be really bogged down at 1100 rpms at 70...it's just a lot of stress on the engine if it really is running at that, though I doubt it is.

[mp4 player]

In my 2000 manual V6 in 5th, 70mph is 2050rpm. Stock 3.27's.

[Gandolf]

If it suddenly seems different, the gears physically can't change themselves. That is super slow for even a V8 in overdrive at 70MPH. Does the car actually feel like the engine is going that slow. If it was, the engine would be heavily loaded and very sluggish (try slowing down to 30)... But I am thinking that some racing tranny mechanic did not switch out your drive train in the dark of night there

The tachometer gage has a problem and the engine speed is really perfectly normal. Take a close look at the tach's readings and see if it is only reading 1/2 the real RPM or sticking. Like the rest of the gages, the tach meter on the dash can fail too.

Check the RPM calculator here which I think is already set for your car:

Ford Mustang: Mustang Tech: Calculators & Decoders: RPM Calculator

It says 2037 RPM. I missed your simple EGR problem for an O2 sensor heater But try again I will!!

Gandolf

[sn95 mustang kg]

Everyday I drive it that way it's getting worse my RPMs at 60mph are under a 1000 and it acts like it going to stall on me...( like when you in 3rd gear trying to do 10mph) I think i got a big problem....

[Gandolf]

Originally Posted by sn95 mustang kg Everyday I drive it that way it's getting worse my RPMs at 60mph are under a 1000 and it acts like it going to stall on me...( like when you in 3rd gear trying to do 10mph) I think i got a big problem....

WOW!!!

I have a hard time imagining that it is a mechanical gear problem... Unless like the transmission or rear end is physically grinding up. Maybe the engine control computer is failing...

I can imagine a bad clutch slipping and overheating at highway speed. So the engine just falls back towards idle. But that should over rev if you touch on more throttle.

This problem should be loud grinding or smoking...

That is all I can think of and it isn't much...

Gandolf

Wait a minute!!!!!!!!!!!

The distributer controls the tach and engine on the ECC-IV if I remember! There is a distributor 'module' on them. I read the Ford patent on how that was supposed to fail "pleasantly" over time once from heat stress... If that module overheats (like at highway speed), it could give false RPM to the tach and generally FU everything!!

Distributer reluctor, reluctor pickup, and distributer module along with the connectors and wiring is a real possibility here! Oddly, if the distributor signal to the PCM goes bat s**t just a little for a very short time, the engine computer will guess and fill in for the failed data. - And probably not report it...

[TheAntiricer]

Originally Posted by 99 BLUE V6 Do you have taller than stock rear tires?

do bigger wheels affect crusing speeds?? i have a 95 v6 whit an auto tranny (stock gearing for now) and at 60mph im at 1400rpms or so and i have 01 mustang gt rims (17's and 245's) is this too low?

[03_StangGuy]

Originally Posted by sn95 mustang kg Everyday I drive it that way it's getting worse my RPMs at 60mph are under a 1000 and it acts like it going to stall on me...( like when you in 3rd gear trying to do 10mph) I think i got a big problem....

Somethin is wrong. The gearing cant be changed. If gears broke you wouldnt move, Your engine wouldnt run any slower. Im assuming your running with traffic when your doin 60-70 mph? Somethin is wrong with your tach reading and that could lead the engine to think its goin much slower than it is and really mess things up. Id get the checked out ASAP!

[9986paulk]

Originally Posted by TheAntiricer do bigger wheels affect crusing speeds?? i have a 95 v6 whit an auto tranny (stock gearing for now) and at 60mph im at 1400rpms or so and i have 01 mustang gt rims (17's and 245's) is this too low?

Your engine is going to be under significant load, and it's most likely not as efficient and is more wear on your engine. For a 150 hp engine, going 2k is easier and more efficiant than lugging along at a lower rpm. That seems a bit low to me, if you really want to keep the wheels, you should go to 3.73 gears. You'd enjoy that too, going up one whole gear ratio.

Edit: And I have some stock gears and differential laying here (~42k) in great shape I'd let go for like $40. They're 3.27 ratio, if you're not really looking for any higher ratio.