running rough at idle and idle throttle...

[hysteria]

so i don't really know what to search for on this one, because my problem's not completely related to the idle. i haven't tried to tackle the problem just yet but i wanted to see if i can get ideas before going into it...

i just installed my fmic, and then the problems started. blocked the iacv off a while ago and the car ran fine for a few months, and then a few weeks ago i installed my fmic and it started with these symptoms...so anyway here's the symptoms: the car runs kind of rough, like hesitates and what not, under certain conditions. these condtions are:1) at idle just after start up, but once the car warms up it stops running as rough. it runs as if it is missing a cylinder, but not on every rotation... it's kind of irratic... it'll miss a few times then run okay then miss and then okay and it just does it at will, not really a pattern to it.2) at low idle throttle. what i mean by this is when the throttle is not open very much but is held at a constant place, for example when cruising on the highway, or when cruise control is on.

it has been somewhat consistant in happening just about every time i start the car, as long as it's cold usually, but it doens't have to be cold, and it doesn't do it much on the highway anymore... when i first installed the fmic it had problems on the highway because all the piping wasn't hooked up well, since i was ripping it out the next day to replumb everything. i'm still not completely finished with the plumbing because i am having my bov flange welded on to one of the u bends right now. i know something is just wrong in the install of what i just did, because the car was running perfect until i installed my fmic. i'm sure i can figure it out but any feedback would help because i do need to fix it soon, and i'm always pressed for time... i want to try and tackle it this weekend, if i have the time.

thanks for the help.

[blubottlemax]

Have you checked your plugs? I'm having a similiar issue. My 2 step colder plugs were fouling, I had to go to a 1 step colder. I also found that my timing was a little too retarded. Last but not least, I think I have an IACV issue. I'm going to pull and replace mine with one off of my spare motor.

[hysteria]

one more thing... when i unplug the mafs the car idles perfect, so i'm lead to believe that i'm running lean, as ina vacuum leak, or not enough fuel or something like that... hmm....

[Import_Ant]

yeah I'm willing to bet your issue is fuel related. do you have a fuel gauge or adjustable FPR? when your car starts to act like this see if you can get out and pop the hood, pinch the return fuel line and see if that smooths out your idle. my car is having this same issue because my FPR is going out and i'm not getting high enough fuel pressure (pinching the return line will increase your fuel pressure and help you diagnose if that's the problem)

good luck-Aaron

[Structure240sx]

are u running an safc or similar? i have the same problem with cold start. its the car leaning out until its warmed up. ont he safc i add .2 to the dec air NE1 setting until it warms up

[hysteria]

haha!! i fixed the problem over the weekend.earlier me and my friend had hooked up eveything quick as a temporary solution and one of the pipes he connected (between the mafs and the turbo) was not hooked up right, but was at an angle that you couldn't see. so i was right about air getting in but not going through the mafs. now the car runs great again!!! thanks for the replies

structure, i have a rrfpr. basic entry level setup with a large fmic and some other stuff.