So I have been running a PR4 on my Si (no major mods) now for years. Every year when its time for emissions I re-install my PM6 to get the car to pass. Well this year I do the same, and the car runs like hell after putting on the PM6. It idles sporadically, starts to smoke and bucks and hesitates at low to mid range throttle. So i tried another PM6 from a friend's car...samething. Then I tried A pg7 I used to run, the car did better but was still hesitating and bucking slightly under low to mid throttle application. So what the hell is this? Why will my car only run well with the PR4? Input would be appreciated.

 

doesn't the PR4 run richer? I'm no expert, but I would think that it has something to do with a poorly functioning sensor somewhere.

 

something is wrong, is everything stock?

 

Why are you running a pr4 on a d16? or a pm6 on a b18a? Why do you need to replace your ecu to pass emissions? do you live in california? i have a pr4 on my ls though i should have a p75nand pass emissions in PA and NYC

 

Yeah the PR4 runs richer. Yup everything is stock. The reason I put on the PR4 was curiousity. It makes the d16 pull great. When I have the emissions checked with the PR3 the nox are thru the roof. I do have a chronic code 1 that refuses to go away (tried 3 different O2 sensors [NTK, Denso, Bosch]). Otherwise the car runs great as long as the PR4 is installed.