SloEG

Most of the time, when I start my car, the rpm would jump right up to 1750 rpm and start warming up from there. Random times, it would only jump to 1250 rpm or right below 1500 rpm and would kinda bog between that range and after 10-30 secs., it will jump to 1750rpm and start warming up as usual. Sometimes it would be below 1000 rpm and after couple secs, it go jump pass 1500 rpm and start warming up. This happens at any time, whether my engine was started first time of the day, at night, daytime, even after couple hours of driving. It just happens like 1/10 times or so. I'm running a 00' B16a2, I already changed out my oil, oil/fuel filters, spark plugs, distributor rotor, and air filter. Distributor cap is still good and throttle body was cleaned. I have no modifcations other than a test pipe and 2.25" mandrel bent piping. If anyone has any idea what could be the problem, please post your thoughts. Only thing I could think of is the IACV (but my idle doesn't jump) or charcoal canister. Sorry for the long post.

deepnite

no for all the opinions..sounds like an emission device gone or going bonkers..vacume hose s, sensors..the worst case , ur ECU

SloEG

I'm running a mugen programmed P28. Never had this problem till about a month or two later. I don't seem to have an vacuum leaks. The thing that bothers me the most is when its bogging below 1k rpm, feels like car is about to dye, and after 10-30 secs of doing that, it'll jump up to 1750 rpm if it hasn't been already warmed.

nwdave

I've had this happen to me too. I never did figure out what the problem was...but it went away

mugendelsol

There is a very good chance it is the mugen program, they run really rich and with the mods you have it could be over loading it with fuel thus creating a very rich mixture

SloEG

Is running the mugen program for a daily driver harmful to the motor, etc? I will be putting in some R cams and manifolds....but not anytime soon.

mugendelsol

from what i understand, no with the cams and such in it will do much better one thing you can do is get the skunk2 chip it is less rich for a stock engine or get a apexi vtec and air fuel montor and an cheep auto meter change and kinda lean the fuel out a little or do some dyno testing ei $$$$. myself i would just get the skunk2 chip and putr it in for now

urbanlegend21

what about checking your fast idle thermo valve?

SloEG

I don't think I have one, my motor is a 2000 model.

DR. ON POINT

02 sensor possibly

SloEG

Oh yea, I get 24mpg with the mugen programmed P28. I doubt it could be my O2 sensor because my car seems to pull pretty strong and everything is new on the motor. Any other signs of a poor O2 sensor? Thanks!