Hey I have a 1997 Dodge avenger es, and I have done a lot of work to it to get it to run right. The car starts like crap in the morning... It usually takes about 5 to 10 mins to start, cause I have to give it gas and lots of it. That happends everytime I start the car. So I replaced the fuel pressure regulator, both o2 sensors. So it ran fine for like a week, then it started to start like crap again. I took it to the mechanics they said the fuel pressure regulator was bad and replace it..so I sent it back got a new one, still no go. Now it miss fires while running it idles rough beyond beleif and I need to know how to fix is. I also got the engine codes 12 and 43. 12 is the battery disconected and the 43 is the multiple cylinders miss fire.

 

List your mods Akihiro and I can try and help from there. Don't skimp on mods because every little one can have an affect.

 

I dont have any kind of mods that would effect that... I have a new clutch that I got when I got the car two years ago, and new brakes and rotors, but nothing that deals with the engine or anything

 

Make sure all four o2 sensors are good. There's two on the firewall side and two on the front side. That may be why you're getting poor idle. You might also want to check plugs and wires...I'm sure you already did that though, make sure you stick with what stock is...bosch I believe. You should take one out and check the tip anyway to see how your car is running. Maybe clean out your injectors with MCCC or Seafoam.