Rough Idle and Accelleration

[Ignacio]

I have a 1991 Mitsubishi Eclipse Gs 2.0 n/t manual trans. I have installed a bent 3'' pipe and the good ol K&N Filter. The rest is stock. Presently My Engine Is Idling Horribly, Low Idle about 500rpm, shaky, Loud. When i Push the accellerator the engine revs very slow and takes a liftetime to get up remember this is in nuetral. When my car ran beautifully it messed up about 2 mins and i thought nothing of it. Then a while later it got worse and it was worse longer but again it fixed itself, Now it is just Weak. I changed my Plugs and My Fuel Filter. I am hoping someone can help me so i can trade my car in for a gst thank You​

 

[StockTSI]

Could be the plug wires. Check the spacing on the spark plugs, sounds to me like a cylinder is missing. Make sure you clean all the connections between the plug wires and the spark plugs, clean out any oil thats accumulated in the well. If that doesn't work could be a fuel injector, also check the battery voltage. I know on Turbo's the coil packs take a well charged battery/ bad alternator or they can do wierd stuff like this, I don't know if N/A have coil packs or if they have this problem.