How should I explain this.... first of when I start my car it idles around 1500 then when it gets warm if drops to about 1000 but then it will start dropping to around 800 like it's going to die but then picks up again to about 1000-1200 and stays on... I've actually just left it there to see if it will actually die but so far it hasn't yet... I'm just curious in what it could be... I have an aem intake and I've read somewhere that that could cost the engine to idle ruff because of all the vibration from the aftermarket piping but could it be anything else?? I just got the car recently and I have no idea what the previous owner had done to it.... but it's pretty safe to say it used to be modified.... should I get a compresion test done to see if anythying is not holding?? There are no ticking sound on the motor the only other issue is the fan turns on quite a bit even when the car is not really that hot... thanks..

 

Wait wait slow down lol. Okay first off you mentions things about the piping on the car. buy some t-bolt clamps for your can and start tying down the vacuum lines with zip ties to stop boost leaks. The Evo is very unforgiving because of this.

When the car sees that boost pressure even under boost or at idle is not where the pressure is supposed to be in the working parameters it will not function properly and your car will not run properly.

Does the car lope consistently you say your car is modded I would check for cams because you may have aftermarket cams on your car.

 

Check vacuum lines, especially if you still have the EGR. The lines that run down the back of the intake manifold always pop off. The lines go from the throttle body to the back of the intake manifold and down.

Also, could be a dirty maf. Likely not, but possible still.

 

i've checked all the clamps and made sure all are tight and secure... i've also installed an after market boost gauge which is electronic and along with the manual boost gauge it comes with and they both seem to hold steady with no problem...

how do i check for aftermarket cams with out taking off the cover??

 

i've checked all the airlines and nothing seems to be out of place... unless i miss something... i will double check again in the morning.. thanks..