When I am going up hill my '97 1.8 engine surges. My foot will stay steady on the gas and no matter how steep the hill it or the speed I am going it surges about 300-400 rpm. Anyone else heard of this or have this issue?

 

I have the same car, but I don't seem to understand, as the steepness of the hill seems to not affect the problem (??) - hills can be almost flat.

Keep in mind that I have no idea why this happens, but this is what I suspect, after reading the manual when I bought my car:

The automatic transmission is electronically controlled to accommodate how you have been driving. I'm not sure, but I suspect it is some sort of moving average. If you are going at a certain speed (flat surface) and then get on a hill (steep surface), the car will start slowing down due to gravity. Your car doesn't know what happened as it does not have hill detection, but it will down shift to maintain speed with the same throttle application.

In summary, the car is probably just down-shifting to a lower gear; mine does it on hills as well. You could perhaps test this theory as well by checking out how your car deals with the transmission control: try taking your car for a nice easy ride, stop the car and see how fast you can accelerate it to ~40mph; stop the car again and see how long it takes to get to 40mph the second time. I would suspect that it takes a shorter time because the car thinks you want it to be more aggressive.

I don't think there is anything wrong with your car, but most of the people on the forum may disagree