I own a 97 mitsubishi eclipse,gs, with 130k miles on it. the car has served me well over the last 40k miles with very little fuss. I have, since, the last 3 months been plagued by this probelm.
* the car stutters like there's no fuel when i am accelerating usually between 50-60mph. it does overcome this, but it keeps happening everytime i get down to this phase. The problem gets progressively worse as I do more miles non-stop. It got so bad twice that the check engine light popped up twice and went away in about 2 days time before i could have the codes read.
* i have flushed the fuel system and done a tune up.. to fix the probelm..but it doess'nt seem to have made a difference, however, imediately after the tune up for a day or two it seemed alright, but then got back to being the same way.
* when idling i can tell from the rpm and just the way the car feels that every now and then the idling fluctuates. and finally it does misfire after a long drive when i step on the gas.
* i do suspect the tune up was not done properly, and maybe I need new plugs or a coil pack, but would love to hear any suggestion from someone who's seen these symptons before.
thank you for you patience.
Never worked on an eclipse but what you are describing sounds to me like partially clogged fuel injectors or a fuel filter problem. Especially even if a tune up (even a poorly done one) didnt show a little improvement.
even though the engine light went away the ECM should've stored the codes and although Autozone can't read them maybe you can find someone that can. this will point you somewhere before you just start replacing parts.
as a matter of fact i believe that you don't even need a scanner for this if you cycle the key 3 times and leave the ignition on,(car not running) on the third time the engine light will flash and give you the codes