question for M6'ers

what is the slowest you guys drive on the freeway in 6th gear? i live in oregon, commute through portland where traffic is routinely 55-60 especially through the 50mph zones of I-5. if i'm in 6th at that speed, rpm's are pretty low, like around 1200. car feels like it's lugging a bit, but will still accelerate (albeit slowly).

my question is this: am i hurthing anything by cruising the car at such low rpm's? i'd love to keep the gas mileage, but don't want to damage anything. i've heard extended driving at low rpm's will foul the plugs????

any input appreciated. thanks.

the owners manual says 6th gear at 50 if i remember correctly

down here in south florida, its flat as hell, so i'll do it at 45ish...but typically 50

on hills no way, or if you need ot speed up

Its it amazing how everyone here seems to follow the speed limit? ANd how curteous and slow they all are? And who's idea was it to make 26 as two lanes both ways?

When I'm on the flat parts of of the highway, I stay in 6th. If I'm going uphill or constantly changing my speed, I go back to 5th..

Now that I have 3.73's, I find myself ilngering in 6th a bit more confortably.

I don't think driving at low engine speeds will foul up our plugs anymore, thanks to sequential fuel injection for each cylinder, an the array of sensors feeding a powerful PCM thats driving it all.

I thought lugging your engine hurt it by the low rpm's causing low oil pressure and too much pressure on the bearing.


Originally posted by Ken S
Its it amazing how everyone here seems to follow the speed limit? ANd how curteous and slow they all are? And who's idea was it to make 26 as two lanes both ways?

When I'm on the flat parts of of the highway, I stay in 6th. If I'm going uphill or constantly changing my speed, I go back to 5th..

Now that I have 3.73's, I find myself ilngering in 6th a bit more confortably.

I don't think driving at low engine speeds will foul up our plugs anymore, thanks to sequential fuel injection for each cylinder, an the array of sensors feeding a powerful PCM thats driving it all.

yea, but if the engine isn't lugging, are you hurting it?

I think its like you only 50 hp to sustain 50 mph or so. Plus if you look in the manual, it tells that we all should be shifting at rediculously low speeds..

This is one of those argument of the ages... goes right up there with how often to change your oil and what shifter is the best.. ;) do whatever you feel comforatble with.


Originally posted by robvas
I thought lugging your engine hurt it by the low rpm's causing low oil pressure and too much pressure on the bearing.

If you stay at 60mph, I don't think you're going to hurt anything.

If you have to go from 60 to 55 to 65 to keep up with traffic (IOW, the people in front of you can't maintain speed) then I think you'd be better off in 5th gear. Also, I think high load in too high a gear was part of the oil consumption problem (example: going 1/2+ throttle at 1500rpms in 6th gear); at least that's what GM said.

I usually go into 6th around 70mph and I'll stay in 6th unless I drop below 65mph or so...or like I said (Ken too), if I constantly have to speed up/slow down, then I'll drive in 5th.

i run mine at 65 mph in 6 th gear she loves it! put it on cruise control ...its all good!:D

Originally posted by 96SFLZ
If you stay at 60mph, I don't think you're going to hurt anything.

If you have to go from 60 to 55 to 65 to keep up with traffic (IOW, the people in front of you can't maintain speed) then I think you'd be better off in 5th gear. Also, I think high load in too high a gear was part of the oil consumption problem (example: going 1/2+ throttle at 1500rpms in 6th gear); at least that's what GM said.

I usually go into 6th around 70mph and I'll stay in 6th unless I drop below 65mph or so...or like I said (Ken too), if I constantly have to speed up/slow down, then I'll drive in 5th.

Same thing here. I only go into 6th gear if I know I will be maintaining that speed. Even if I am crusing on a highway that has some traffic and I know that the speed will be fluctuating, I will stay in 5th. 6th is good for crusing when your speed will basically remain constant and above 60+ mph.

remember 5th is OD and 6th is just double OD so actually ur still in OD in 5th which is what most cars have and they do just fine

I usually try to shift into 6th around 45-50 mph. I cruise at 65-70MPH with 70MPH turning 1900RPM.

I'll cruise at very low speeds/rpms too. As you said 1200 is about the limit before the oil pressure begins to drop. When i am cruising at low rpms like that i don't get on the gas. Just leave the throttle cracked and it pulls it, you can even pick up some speed using very little throttle, you don't have to stay up the other guys bumper ;) If you need to accelerate you can floor it and the motor does have the torque to pull it, BUT i downshift if i'm going to be anywhere close to 1/2 throttle at those rpms. I don't feel that i'm lugging it by driving at such low rpms since i use very little throttle.

-brent