I think that the video will pretty much explain what is happening, but after the car is warm, it will sit at 1k (good) but then it will raise to 2k for acouple of seconds then drop back down for about the same time it was at 2k, then it will repeat. I've tried adjusting the screw on the trottle body, it's all the way down now. I have also switched out the BOV, I have tried the stock one, the MR one and the Forge RS. It's really annoying because people think I'm reving at them. I don't know what to do. Thanks.

 

I see the problem!! Your car is on its side!! It is hard to figure that one out. I will chew on it. no sound on clip??

 

sound would help.......

 

Well, it doesnt sound any different if I were to use the pedal to replicate it.

 

do you have the defroster on? That's what my car does when the vent is set to defrost - AC compressor cycles on and off.

 

Does it with or with out the AC/defroster on.... Could it be that I have an emulated 02 sensor in the rear?

 

The only thing i can think of atm is maybe your iac motor having problems. With that thing having issues your idle can do some weird things. It was more common with the dsm's but i have seen it have issues on a few evo's.

 

dirty maf sensor????

 

My car did that - would go to 1700rpm for 2 sec then 1200rpm for a sec over and over andover.

Well, I started troubleshooting and found that my stepper motor was melted as well as the mysterious internal flapper with no name. Luckily I found a TB for sale and swapt parts

Ops check good

Oh yeah, I confirmed mine was caused by excess methnol trapped in the system and developing vapour lock + fire. This was caused from testing the system with pure methanol - duhh and apparently some alcohol staqyed in and ignited.

Pull your stepper out and inspect the tip - takes 2 minutes. If it's in good shape then its something else

 

Thanks C6C6CH3vo, that could very well be my problem (I was a little happy on testing the meth too). But where is the stepper? Is it all in the throttle body? Pictures would be awesome. Thanks man.

 

all evo does this, is when u have ur vent set at everything(the icon with the window and steam), if u set ur vent to head only or head and feet only, this will go away

 

I have been tracking down this exact problem for a while now. The flapper with no service manual references is frustrating to say the least. What is that allen wrench slot in it for? Is it supposed to be really tensioned or something?

 

If your looking down the throat of the TB, the stepper would be bottom right. It's a black plastic peice with 3 small screws. First remove the electrical connecter by squeezing the release button and pulling gently till it disconnects. Next grab a stubby phillips and remove 3 screws and make sure you dont drop the packing.

The tip of mine was melted. Not saying yours is like this just I had the exact same problem (I use 70% methyl now just in case eventhough I know it was because I flooded it )

 

Ok, I'll check this out today. Thanks for the info. I owe you one if that's the problem.

 

he stated above that it does this even with the defroster off.