ok, now this is the story, my car was doing fine, everything was working excellent, so yesterday i decide to change my air filter, ( HKS COMB ) since i notice it was getting very dirty, im running the AEM intake, so I was going to install the AEM filter, and so I did. after it I decide to inspect and re-tightened the clamps from my intercooler pipes, every thing look good. After I was finish I left the car alone.

Now today when heading to work, I start the car and it kind felt funny like if it was going to die then the rpms came back up, i though maybe because i disconnect the MAF sensor when installing the filter.... and it got to a normal temp and driving to work, It didnt want to boost over 5psi!!! it kinda stutters back, but under 5psi it drives fine.

Now when I got to the parking lot I inspected the whole bay, thinking maybe something blew off, but no everything seems in place, but now in idle the engine shakes a little bit and there seem to be a rattling noise coming down from under the serpentine belt area. I though about the sparkplugs or maybe a coil, but wouldn't that cause a miss fire, and the CEL would come on? cause mines OFF.

what do u guys think?

 

Pull the intake off and make sure everything looks right. If the honeycomb is messed up in the MAF it could make it idle goofy, if something got blocked in the intake (filter fell apart?) it could cause lack of boost. Just take it apart, snap some pics, post them here and we'll try and help.

 

well today actually exchanged MAF sensors with my other friend's evo and it still does the same thing, after driving it for a while, it gave me a code po172 (system too rich) , I took of the front strut bar and start inspecting vacuum hoses 1 by 1 and i found one that was disconnect from a brown sensor right under the intake manifold, I snap the hose back with a zip tie and test drove the vehicle, and it still doesn't the same thing!!!

 

Well sounds to me like you need to reconnect that vaccum hose to that "brown" sensor. That sensor relies on the vaccum to send the right information to the ecu to have proper oporation of your power plant. So just pinching it off and not reconnecting it is of course not going to yeild your motor back to normal. After you do that disconnect the battery for 5 to 10 minutes and let the ecu reset back to its normal range paraimters. Just my 2 cents from what I am picking up through your posts! Thanks

 

well i would go ahead and reset the ecu like nightrider said. but it sounds like a boost leak to me....i know you retightend everything but doesn't mean that it fixed the leaks that you have and in some cases could make it worse just by tightening it. i know i had a clamp on to tight and it made it leak, as soon as i started to loosen it the leak went away. but honestly the car running like **** sounds like text book boost leak. Just a thought....and it's always good to do a leak test period. also the reason i don't think it's the plugs or the coils is because those symptoms started immediately after you changed the filter. and you said you messed with the IC plumbing. so immediately i would rule out the filter.

 

If you didn't re-set the ECU by disconnecting the battery when you went from stock-box air filter, to a cone type. Your cars stuttering is your cars way to tell YOU WTF???!! It is looking for the volume of air in the airbox to compensate for, and it's gone. Reset the ECU with disconnecting your battery for 10 minutes, start the car (DON'T TOUCH GAS PEDAL!) Let it idle for 10 minutes to re-learn the new intake. problem solved.

You change a part on your car, LET THE ECU KNOW you did!! You noobies. LOL. Everytime I see a post like this from a Noobie, I have to shake my head. SEARCH, the answer is in here!! It's funny when one of you changes a simple part, then other newbies say: "A friend of a friend had this same problem, and it was crank-walk". LOL. ITS SIMPLE!! the answer is what nightrider says.