High RPMs on interstates

Hi guys, new member here. I own a 1998 Sunfire. It has the 2.2L engine and an automatic transmission. It's been driven roughly 128,000 miles.

I've noticed on the interstate that the engine RPM's on the tach are much higher than I think they should be. At 55 mph or so, the engine runs around 2500 rpm, which isn't so bad. However at 70 mph, the engine runs at 3500 rpm, and at 80 mph it runs around 4000 rpm. This seems a bit high compared to other cars I've seen with the same engine (Chevy Cavalier and Saturn L-series), which run about 2700 rpm at 70 mph. I know it's not much lower than my Sunfire, but with the engine running this hard at interstate speeds, it dramatically affects the gas milage.

Has anyone else noticed this? Is there a solution to this short of buying a new transmission?

I know on my dads '95 Cavalier 2.2L Automatic that it does rev high on the highway, but it's only a 4 speed with no overdrive. It doesn't have an RPM gauge so I couldn't tell you what it's running at. How long have you owned the car? (miles wise) and has it always been reving at 3500 since you've owned it?

I have a 1995 sunfire withe the 2.2 auto. it does the same thing. since it doesn't have an Overdrive gear, the engine revs high. if you ever drive a 5-speed one, the tach will be at about 2500-2800. thats why standard or overdrive equipped vehicles have better gas mileage. my firechicken has almost 300k miles and it did it at 182k when I got it.