yup mine does this too!!!!but not all the time it only started to do it around 17,000miles so mabe its the plugs or coils!!!stupid evo 9's lol

 

My EVO IX is brand new. Less than 270 miles on the clock, and it has a lumpy or rough idle. My tach doesn't jump like yours unless the cooling fan turns on, but when it's idling at 900, sometimes the engine will shudder or hiccup for a split second. When it does, it causes a light vibration. It's a very faint feeling, but I can notice it at a stop light or just sitting in the garage. No CEL either. It's random too, and sometimes will idle fine for several minutes, then a second later, another hiccup. Almost like a mini-misfire. Some people have told me that the IX's have a lumpy/rough idle stock, but to me, this doesn't feel normal. Could be bad gas, or water in the lines too.. I put in a bottle of Heet yesterday, and I think my shudders aren't as bad as when I first took delivery, but it's still there.

I purchased an Equus 3130 OBDII scanner/reader and should have it by tomorrow. I'll hook it up and see if I pull any DTC's. If I don't get any errors, then I guess I'll just leave it alone.

 

try hooking up an ignition amplifier that has worked on some of our cars dealing with similar probs

 

Did you put back the stock fuel pump, too? If not, I'll guess that it's fuel over-run from the uprated pump.

 

i think is the intake

 

i'd say its the MAF, which can put the blame on the intake or the maf is dirty... good place to start i say.

so first i would try cleaning the maf which is easy and costs little.... if that doesnt work, try putting the stock intake back on.