Does it still falter if you gently open the throttle? Make sure there are no
vacuum leaks on the small hoses, and the big hose to the brake booster.

It sounds like fuel starvation. This can only happen if

a) the fuel filter is clogged, but you say that's been changed.

b) the fuel hose from the filter to the fuel rail is blocked or damaged
internally. Take it off an blow air through it both directions, then see if
a piece of welding wire or similar will pass all the way through. The fuel
rail should have residual pressure for a while when the IGN of off.

c) the injectors are either clogged with gas gum or they are not getting
fired adequately by the ECU. There should be +12V on the thick wire that
connects to the injector. The thin wire is switched to grounded by the ECU.
Pull the injectors out and have a look. If you don't have +12V (should be
the same as alternator/battery voltage) on the injector, look at the MPI
relay behind the radio, then the circuit that supplies +12V to the relay.

d) If the injectors are OK, look at the valve timing. A slipped belt will
allow the engine to idle, but it won't rev.

e) have you swapped out the ECU?

Stewart DIBBS

I had the same problem with the 1.5 liter, 94 mirage. i would start by
unplugging the battery and reset the computer. There were two problems with
my car, one was a small gear in the throttle body. I removed the TB then
removed a small cover on the side to expose the gear. the small gear is
black and part of the teeth were cracked. What i did was reposition the
gear, i believe it ossilates back and forth so i guess (only guessing) i set
it so the teeth engaged all the way. that also seemed to help.

something i also noticed was a small hose (vacuum) off of a solenoid on the
firewall. i put that back and this seemed to correct the bogging while
accelerating. I would look into both of these things. I acutally had to
drive the car while it was bogging, it was something esle trying to climb
hills. I had to get a running start, the car would bearly accellerate in ea.
gear.

Hope this helps. BTW, Stew is VERY knowlegable with these things..