Well 2 weeks ago I installed a mazdaspeed cold air intake and exhaust. Ever since my car slightly shakes and when I come to a stop the rpm drops to 500, as if it wants do turn off but it never dose it just gos bake to normal 700. So what should I do?

 

Whats the year and model of the car? AT or MT? miles?

 

rx8 gt 2004, 30508 miles, MT.

 

Have you ever changed your plugs or coils? With that much mileage, it would be a good idea.

 

you likely have a vacuum leak..

check the connections on the intake..

beers

 

Ya I did change the plugs and coils. Also when I put the mazdaspeed cold air intake on, the manual said I had to take the vacuum off. It came with a plug to close off the vacuum hose

 

https://www.rx8club.com/showthread.p...82#post2650882

Same nipple, same problem....

S

 

I had to take mine off. Does that mean I’m always ganna have that problem. Is there any whey I can fix it? I had to take the entire vacuum off.

 

Did you plug off the nipple?


....or is it still sucking air?

S

 

Ya I plugged it off.

 

I have had a similar problem with my Mazdaspeed CAI, it has been installed for a little over 2 years now. I am not sure if it was a coincidence or not, but I believe my idle has been rougher with the install. I also plugged off this vacuum line.

I have checked and cleaned my MAF - no improvement.

Will probably be looking for vacuum leaks on the install and also take a look at my throttle body to be sure there is no build-up do to oil carryover, etc.

2nd thing would be to change my coils and spark plugs to see if that will help the problem.

Last thing would be a compression test by the dealer to see if my engine is going (common for 04's)

I have been living with the rougher idle, but seems to be getting a bit worse...

 

Ive read some intakes remove a maf screen or screens? and warn of possible idle issues. are these screens in the factory airbox assy or in the plastic intake tube? I havent even taken my airbox apart yet

I know in a eclipse/evo the miniscule amount of airflow gained by removing the air staightening screens or honeycombs in a DSM isnt worth the issues that come from screen removal.

 

yeah i also would reccommend replacing the plugs/wires and coils but I would double check around the intake for a vaccum leak it does sound somewhat like that

 

Checked for a vacuum leak, didnt find anything. I did replace the vacuum plug on the underside of the throttle body - it was rotted, cracked and about to fall off, but this did not help the idle.

Also, checked the throttle body - 63,000 miles and clean, spring working fine - no sign of oil or build-up.

Has anyone checked the vacuum on the intake header using a vacuum gauge (connect to nipple on header - currently plugged) - passenger side of the car?

 

Try pulling the 'room' fuse (drivers footwell fusebox) and take a test drive,
see if that evens out the idle......

S

 

StealthTL, what is your thought on the room fuse pull?

The room fuse powers the memory of your ECU and powers the interior lights..correct??

Couldn't I just pull the battery cables ((which I have recently) and accomplish the same thing? You have any more info?

Thanks.

 

The room fuse does power the memory, but if you just pull the cable the ECU will build new STF and LTF trims, which could be screwy. Driving with the fuse out prevents new trims loading, sort of puts it back to factory stock.

S

 

i'm taking my car to the dealership next week. i'll let you guys know what happens.

 

Stealth - Are you saying to run for about 50-100 miles without the fuse then re-install (to allow the car to relearn) or just to pull and then reinstall prior to driving.

 

Just ten minutes should do it - a cruise with no fuel trims will tell you if it's 'hardware or software'.

S