Better off in a lower gear? (city cruising)

[JeepNmpg2]

Though I'm driving an automatic, the FE in my higher gears isn't so great until I'm above 1800 rpm and I have a torque geared engine.

My $.02...

[JRMichler]

I find that knowing throttle position is not very useful, especially at low RPM. I watch MAP - Manifold Absolute Pressure. It's the opposite of manifold vacuum.

My 2.8L engine does not seem to lug. It does shake at low RPM and high MAP.

[user removed]

My VX would cruise along at 30 MPH in 5th gear at 1000 RPM. Not a good choice for acceleration which would usually be 3rd gear unless much greater acceleration was needed then it would be 2nd gear.
3rd gear was good to over 100 MPH in the VX.
If you are just maintaining speed go to the highest gear. Use the lower gears for acceleration depending on the rate you you desire.
AS long as you are not accelerating you need not worry about lugging unless your RPM drops below 1000.

regards
Mech

[99LeCouch]

My Cruze will happily putter along at 30 mph at 1000 RPM in 5th when there's very little load on the engine. Seeing it's a DBW throttle and a very "smart" computer, it's nigh well impossible to lug this engine. I do that when there's a long way to go at 30 mph. Any accelerating and I'm rowing the gears to go faster.

[sid]

My Ranger will also cruise acceptably at 30 mph in fifth. Much below that and it starts to either lose speed or lug (and threaten to stall out), depending upon the throttle position. There is a narrow range, about 25 to 29 mph, where I get best FE in fourth gear, and the FE still reasonably acceptable for this truck, around 40+ mpg.

[Kodak]

hmm. sid, what's your rear end ratio?