Rough idle

[Rpep]

Hey all. New here. So I just bought an 02 protege5 5 speed with 155,000 miles. Seller took really good care of it and it was running great when I bought it. I did some small upgrades: 7mm ultra plug wires, new ngk vpower resistor spark plugs and a short ram intake. It now all the sudden is idling rough when coming to a stop. At a stop it idles at around 700 to 800 rpm then spudders and returns to the same rpm. It always ran smooth at 800 rpm prior to the upgrades. Not sure it in the process the MAS sensor got dirty. Will try cleaning it. Anyone else experience this or have any other ideas.

 

[The_big_dill]

Did you install a cheap intake or a name brand? Make sure there are no vacuum leaks.

Clean EGR if you strike out with any simple solution.

 

[Rpep]

It was a cheap one. Will get a better one soon but have consiplated putting the stock intake back on. Cleaned the MAFS it had some debris. I put the old plugs and stock plug wires back in and the idle got a little better. Not sure if maybe it just didn't l I ke the different plugs and wires. Changing back helped some. It has developed a small ticking sound when pushing the gas peddle to accelerate between 2500 and 3000 rpm. When I let off the gas it goes away. It happens intermittently and stops when sitting at idle. Hoping it's just a vacuum leak somewhere not the valves or worse. This is my first mazda and I really like this car but if it has tons of issues not sure. Any help is greatly appreciated.

 

[Brinkly]

I've learned that sometimes the brand of the spark plugs can have an effect on the way that the vehicle runs. I would definitely search for any vacuum leaks before really diving into this problem. Sometimes it's just as simple as that.

 

[Maroon]

Who hasn't experience an idle issue with this car? I've put 125,000 miles on this car and the idle has been consistently inconsistent. It is nice when it randomly decides to idle steady at 800 rpm for a month or 2.

Try cleaning the EGR. Do you have any exhaust leaks before the 02 sensors?

Really, I think it comes down to the ECU just being an idiot. Try unplugging the battery for a couple minutes. Upon restarting, it will run weird, but maybe it will relearn differently.

 

[katapaltes]

^ Me. Except for when the coils were going, and then it was idling weird. But only then. My P5 wakes up hard and stays hard all day long, I like to say.


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[justin1194]

It was a cheap one. Will get a better one soon but have consiplated putting the stock intake back on. Cleaned the MAFS it had some debris. I put the old plugs and stock plug wires back in and the idle got a little better. Not sure if maybe it just didn't l I ke the different plugs and wires. Changing back helped some. It has developed a small ticking sound when pushing the gas peddle to accelerate between 2500 and 3000 rpm. When I let off the gas it goes away. It happens intermittently and stops when sitting at idle. Hoping it's just a vacuum leak somewhere not the valves or worse. This is my first mazda and I really like this car but if it has tons of issues not sure. Any help is greatly appreciated.

As Brinkly stated above,

The brand and type of the spark plugs really do make a difference. Which are you running?

 

[Rpep]

So it had iridium plugs prior and I switched to the ngk vpower resistor plugs. Upgraded to 7mm ultra plug wires as well. I did put back the old plugs and plug wires and idle got better. This morning on the way to work after warming up the check engine light came on and a ticking sound started. I will go the autozone to see what the code is. Maybe exhaust leak but not sure. It's not losing any power.

 

[Rpep]

So I found that a vacuum line came off the throttle body causing the idle issue. Easy fix just took time for me to find it. Took it in for a radiator flush and they found that the head gasket was leaking internally. The valves are out of adjustment causing the ticking noise. Good thing is we caught it early so no major damage. A little machine work on the head and valves. The radiator is getting replaced and all the hoses. New water pump and timing belt. So a huge overhaul in the works. So I better get a whole lot of miles and use in this car lol. Did order a injen cold air intake in black, will look sweet. My suby sti lower lip came in also. Can't wait to get the car back to get these installed. Wish me luck!