Last post on Sep 14, 2013 at 9:34 AM
You are in the Mazda Protege
What is this discussion about?
Mazda Protege5, Hatchback, Sedan
#798 of 1420 Re: Idle Problem on Mazda Protege 5 [kuruptboi]
May 04, 2005 (4:30 am)
Go back and ask those dunces to check your car's "Idle Air Control Valve." It's a vacuum- or computer-controlled valve on or near your intake manifold that controls idle speed. My 1994 Mazda pickup had an IAC Valve which, like most other things under its Ford-engined hood, needed replacing after about 50,000 miles. My 1978 Toyota Corolla had the same symptoms you're describing and it was fixed by replacing the IAC Valve.
Since your car is only two years old and has only 30,000 miles on it, this is a warranty-covered repair. Take it in and demand service!!!
It probably failed because of carbon deposit build-up in your throttle body and on the IAC Valve's little sensor that sits in the airstream going into your engine. This begs a question: What brand and octane of gas do you use? I'd ask more questions, like how often you replace your fuel and air filters, but at only 30,000 miles I don't suspect they'd be the culprit. Poor gas or using an improper octane rating could do it, though.
So could using a K&N Filter. (Uh-oh, don't tell all those K&N addicts out there!!!) Too much oil on the filter can cause oil to enter the throttle body and gum up a lot of stuff that was designed for nice, dry air -- not oily air. (A lot of Ford Mass Airflow Sensors have had their coils damaged by oil from K&N filters.)
Here's a link showing a typical IAC Valve problem:
#799 of 1420 Re: Idle Problem on Mazda Protege 5 [mdaffron]
May 04, 2005 (9:42 am)
I actually had the Idle Air Control Valve and gaskets replaced on it the first time it was in the shop. The car ran fine for a couple days then it was back to the same problem.
I then took it to another Mazda dealership/service closer to my work. They told me that they forgot to set the base idle in the computer when the previous service shop reset the computer for the IAC. They told me that it was set and told me it was ready. I picked the car up after 6pm, meaning there was no one there but the lady with the keys. The car was still screwy.
I took it back and told them it wasn't fixed so they called up Mazda Tech line and they told them to disconnect the battery to reset the computer and all the codes. Once this was done the care drove fine for 2 weeks.
At the end of the second week the symptoms returned. I took it back to that same shop and they had no idea what to do so they just disconnected the battery again and told me to put the stock exhaust back on because the Tech line said it may be a backflow problem with my exhaust. I have a Greddy Evo 2 exhaust on there, which is free flowing, so i know that is not the problem. They gave me the car back and it drove fine for a couple days, only to have the same problems.
I also have an Injen cold air intake on the car, if the sensor on that is malfunctioning could that cause the problem. I am searching frantically for the problem. It seems as though no one knows how to fix the damn thing and of course the dealership/service dept always blame it on the aftermarket parts.
Thanks for the feedback, hopefully this extra info might spark some new ideas.
#800 of 1420 Re: Idle Problem on Mazda Protege 5 [kuruptboi]
May 05, 2005 (8:43 am)
I hate to say it, but put the original exhaust back on along with getting rid of the cold air intake. Not enough back pressure in the exhaust can also cause problems.
Seriously though, stop messing with intake and exhaust mods when you have no way of tuning the fuel injection properly. If you wanted a faster car you should have bought a faster car.
#801 of 1420 Re: Idle Problem on Mazda Protege 5 [kuruptboi]
May 05, 2005 (8:54 am)
Also, Mdaffron is correct in asking what octane gas you are running. Alot of people try and run higher octane gas than what a car needs, fooling themselves by thinking it provides magic horsepower. High octane gas needs "high compression" in order to burn completely. Unburned fuel will leave carbon deposits and screw up any exhaust sensors down the line. Running higher octane gas than what the car manufacturer recommends is a good way of wasting money and destroying your engine.
#802 of 1420 Re: Idle Problem on Mazda Protege 5 [iamz]
May 05, 2005 (12:45 pm)
fair enough but why would the car run completely fine for 2 years with the mod parts on there and now all of a sudden issues have arisen. i use regular unleaded gas btw.
#803 of 1420 Re: Idle Problem on Mazda Protege 5 [kuruptboi]
May 05, 2005 (4:05 pm)
What has me confused is that the problem seems to go away for a couple of days to a couple of weeks every time they work on it, but then comes back. A bad sensor should stay bad.....A vacuum leak should keep leaking. A bad chip should stay bad. Fuel pumps and clogged fuel filters act up at higher rpm's and not at idle. Hmmmmmm?
Moisture can affect electrical parts intermittently. When it first starts to act up, did you just wash the car, or was it raining, or was the humidity high?
#804 of 1420 Re: Idle Problem on Mazda Protege 5 [iamz]
May 05, 2005 (6:11 pm)
that is what has me confused as well. get this: today was the first day in a couple weeks that it has been over 60 degrees and the car ran flawlessly. the car has been slipping and acting up for 2 weeks solid, whether the car has been running for a while or not. i am not sure if this is a coincidence but i am taking it in for service saturday (brake pads/oil) and i will mention it to them. i am starting to think my car is possessed... either that or only like warm weather.
#805 of 1420 Re: Idle Problem on Mazda Protege 5 [kuruptboi]
May 06, 2005 (4:36 am)
just an update on the previous post. cold this morning (44 degrees or so) and the car is acting up again. seems like the temperature outside is affecting the performance of my car. thoughts....ideas?
#806 of 1420 Re: Idle Problem on Mazda Protege 5 [kuruptboi]
May 06, 2005 (7:29 am)
I can't explain why in previous cold weather of the last two years your modifications wouldn't have caused trouble but do now, (not saying they are the cause but just speculating) but if your car is only acting up when it is cold, it leads me to look at your cold air intake again. I would try going back to the original stock set-up that allows warm air to be mixed in as an experiment, since it would be relatively easy to do.
#807 of 1420 Re: Idle Problem on Mazda Protege 5 [iamz]
May 06, 2005 (10:27 am)
that is what i planned on doing if the dealership couldn't figure anything out while it is in the shop tomorrow.