Mitsubishi Repair: loss of power, vacuum leaks, intake plenum

Question
hi there i am a mechanic at a gm dealer and i have a friend who want me to work on her car. she has a 1998 eclipse 2.0 gsx maual. she has had some problems with it lately. like no power, when she drops it into 2nd gear and gose around a corner it will sound like a back fire. the check engine like stays on but when it spits like that it will blink like 5 times then stop then i think 9 then 3 more times now i went for a drive with her to show me. i think it one needs a tune up. but most of all i think it could be fule filter and plugs i have an idea on leaning to the pcv valve but i am not to sure if you could lead me in the right direction on where to start i would like it very much thanks garrett

p.s i hope i gave you a prity good discription

Answer
Garrett,
Definitely perform a tune-up.  The plugs, plug wires, PCV valve, air filter, and fuel filter should all be changed.  Also check the timing to be sure it's ok.  Inspect the IAC motor and EGR valve.  These turbo models have several small vacuum lines that may come loose or even get cut.  Vacuum leaks can cause this problem.

It may be good to pull and clean the throttle body assembly, the intake plenum, and the intercooler.  Over time, these items accumulate lots of oily residue and will reduce power and can cause stalling if it gets bad enough.
Good luck!