right, this problem has come up 3 times since i bought the car. brought it to a mechanic and he doesnt have a clue.
The car would normally idle at around 800 rpm when its warm but now its idling at around 2100 rpm, but thats not all. It would then start to rev up to about 2500 rpm and drop back down. It would do that about 20 times and then level out at 2100 rpm again.
Sometimes it can drop down to 1500 and then start reving up and down to about 2000 rpm.
It hard to explain so i took a video of it happening,
Any help would really be appreciated!!
common problem on the b6 engines from what i understand. there are a lot of ideas on what it is. could be the iac, take the throttle body off, spray it down with brake cleaner to get all the gunk out make sure to clean out the iac on the bottom part of the TB. Also it could be a vacuum leak somewhere so check on that, lastly it could just be the grounds in the engine bay are starting to loose effectiveness, so just replace the grounds with better wires or add a good engine ground kit, if you do some research on mx-3.com or clubprotege.com someone posted the best places to add the grounds
oh thank god.
which part of the throttle body is the iac?
sorry, but it still says newbie under my name!!
i'll try and find a parts blowup in pdf and email it to you or post it
cool, thanks but i took off the throttle body, cleaned as much as i could and its still the same.
any other ideas?!
did you check all of the vaccum hoses? and check the electrical load cause like i said both of those can be issues
On the front rocker you have a black breather pipe with a PCV valve in the end that plums into the rocker. Check that it is sealed correctly around the black washer at its base. Mine had a slight air leak there and would cause the idle to variy.
PCV = Positve Crankcase Valve it allows the blow by gases to exit the head and re-enter the inlet it has a ball valve which ocasionaly can get stuck or wear. If it has an air leak it screws the idle up as it is past the AFM ( Air Flow Meter ). Or if it gets stuck and increases gas pressure in the head.
I think you mean Positive Crankcase Ventilation. :wink:
my vacuum hoses are a mess, they are all over the place and some of them have electrical tape covering the ends of them. im just gonna have to bring it to a mazda garage and let them sort it.
sorry mechanic, i have the 1.6 DOHC, should have made that clear!!
Thanks though guys