swap or not

I have a 93 metro that is hiccupping, mostly when accelerating but will sometimes run all day with out a problem. The problem started this winter and only happened at speeds above 55, but now at any speed, it almost feels like a complete loss of power than right back in less than a second. I replaced the gas filter and it seemed to work fine for a day but the problem was back the next day. I have checked the distributor, plugs, coil, and wires all OK. Anyway I am looking for suggestions as to what else it could be. Also want to know how hard it would be to swap the engine out, as I have a 1990 metro that the front tire "ball joint" fell off of, but the motor is still good. Would I have to change out the ECM? And if I do, does that mean I need to change sensors etc... Also how hard is it to get the ECM out? The Haynes book does not even show where it is.
Any help would be appreciated.
Mike.

Not sure as to your root cause for your problem, but if you do decide to swap, here are some suggestions. It would be smart to swap the ECM. It is located under the dashboard on the driver's side. It is above the fuse block. Pull the fuse panel out, and the ECM will be staring you in the face. It's a gold unit with two braces that hold it up. Anyway, most sensors will interchange assuming the transmission is the same. If not, your throttle position sensor (if Auto) will need to be changed for a throttle switch (if manual), or vice versa. Also, from 1989-1991, Metro models (except those originally sold in California or otherwise equipped with the Californian emissions package) did not have an EGR valve. So if you swap an older engine into a newer car, you are going to have a spare sensor connector. Since your doner engine's ECM follows you into the new car, this won't cause a Check Engine light. Also, if the main seal in the doner engine is old, now would be the time to change it, even if it is not leaking. They are not expensive and when it does start to leak, which it will eventually, you will kick yourself for not changing it now. Also, if you have a manual tranny, now's a good time for a new clutch.

To swap the engine out, you'll have to change the ECU, and wiring harness. You'll also have to splice the engine side wiring harness into the plug that goes to the inside of the car. The plugs are very different where the 2 wiring harnesses join from the 90 to 93.

Thanks for the info! It looks like I have a project for this summer.