My car idles at around 1150rpms. mods: m2 cold air intake, catback, and downpipe

At this idle the car sounds real unsteady. The sound is just filled with constant pops that sound a little like the backfiring i get when i downshift before the car is warmed up, just not as loud

'pop pop pop,' they go at random increments. they go off at least once every 2-3 seconds, sometimes 3 or 4 times in the span of just a few seconds. the pops sound pretty muffled, but its still annoying

now, when i turn the lights on and depress the brake when stopped (or even raise/lower a window) i can drop the idle to 750 or 850 (either, depending on how long i mess with the electrical stuff)

turning on my emergency lights will lower the idle too. now, when i stop messing with all of this stuff i can get the idle to hold steady and there are none of the muffled pops at all, just a perfectly steady idle. why?

also - one more quick thing to add... if im stopped and i rev the engine to 3k, it will literally 'pop' itself down to the 1150-1200 idle. itll pop like 10-15 times in the time it takes to drop the idle (just a few seconds)

if this isn't some sort of problem then i dont really mind, its just sort of embarassing because it sounds so crummy, but i can deal with it

anyone know whats up with my car? thanks

-nill

 

by the way, when i lower the idle to 750 (takes about 10sec of messin with electrical things) the turbos read around 19-20, on a good day 21 :p

 

By this do you mean that you have a vacuum reading on a boost/vacuum gauge of 20 or so inches of mercury being pulled for vacuum?

As for the other deal....that is a little odd, but the cars DO respond to an increased electrical load, however usually it is the other way around; meaning you turn on the lights or some other heavy electrical drain and the idle will increase slightly.

Any other mods than what you've mentioned earlier?

 

hehe sorry, i meant 20mg (i forgot what the units are called) on my boost gauge (negative 20 on the gauge)

no i dont have any other mods that i know of

i bought the car used with pretty new engine in it and 80k on the chassy (engine has like 6k-7k now)

ive also boosted 15psi (accident, trust me) on a supposed stock ECU on multiple occaisions (i know its stupid, and that im lucky)

i hit 12-13 all the time and am in the process of getting a boost controller so i can actually give my car some w0t :p


i agree with you that i think its weird as well. whenever i turn on one of these parts that requires electricity it surges up before it falls (just for a split second and only a very small amt of rpms, like 50-100)

 

basically, im starting to think that the original owner put in a new ecu. ill have to check it out

 

Yeah, it sounds like you have some sort of ECU issue....make sure that someone hasn't done one of the "fan mods" that allows the fans to stay on after shut off, and left a wire bare to ground out or something. Maybe you can just reset the ECU by disconnecting the battery and pushing the brake pedal 3 times.
It is worth a try.....

 

Did you do the following:

1. Close AAS screw on bottom of TB to almost completely shut (clockwise direction)?

2. Back out TB linkage stop so TB has no pre-load on it (screw near top of TB).

3. Adjust TPS sensor.

4. Disconnect ISC to verify that engine dies with it disconnected (it should).