New air filter: Now have rough idle?

[JEDI]

it's the same air filter as the old one.

at my first light at the end of my block, my car started shaking, which has never happened before.

car was fine after it got warmed up.
So why would a new air filter cause rough idle?

 

[cabri]

Put the old filter back in.
If the problem still exists, then it is not the filter.

 

[JEDI]

Put the old filter back in.
If the problem still exists, then it is not the filter.

doh.. tossed it

 

[Jimzz]

sigh... Year, Make, model, and engine?

Check the air box VERY well. Many have sensors and/or emission lines/hoses running to them.

 

[master_shake_]

What the guy above me said

 

[BUTCH1]

Maybe you should hire a mechanic for your needs, you don't seem "mechanically inclined" at all.

 

[boomerang]

Maybe you should hire a mechanic for your needs, you don't seem "mechanically inclined" at all.

It's been said that smart men know their limitations.

 

[phucheneh]

Air filter has nothing to do with it. You could run a new air filter. An old air filter. Hell, shove a stray cat in there. It's not going to affect how the car idles.

You either knocked a hose loose that is behind the MAF (allowing unmetered air to enter the throttle) or the MAF came unplugged. Those are about your only options, barring an EXTREMELY overcomplicated air filter installed that required more than just pushing the intake tube to the side so you could get the filters in/out.

 

[JEDI]

sigh... Year, Make, model, and engine?

Check the air box VERY well. Many have sensors and/or emission lines/hoses running to them.

2005 mazda3i, 2.0L automatic, 175k miles.

I did recheck the air filter box. all the straps are securely in place.
the maf sensor seems secure. no idea about the rest?

 

[JEDI]

Air filter has nothing to do with it. You could run a new air filter. An old air filter. Hell, shove a stray cat in there. It's not going to affect how the car idles.

You either knocked a hose loose that is behind the MAF (allowing unmetered air to enter the throttle) or the MAF came unplugged. Those are about your only options, barring an EXTREMELY overcomplicated air filter installed that required more than just pushing the intake tube to the side so you could get the filters in/out.

ok.. will check all along the maf

 

[LTC8K6]

Was possibly just re-learning it's idle?

 

[JEDI]

Was possibly just re-learning it's idle?

opening the air box would make the car relearn its idle?

 

[LTC8K6]

opening the air box would make the car relearn its idle?

If the old filter was really dirty...

But the re-learn should be over pretty quickly.

It's a long shot, I admit.

One other possibility. You had an air leak, which your pcm had adjusted for, and you fixed the leak when you replaced the air filter.

Did you happen to disconnect the battery?

 

[Pacfanweb]

Just check the installation. You may well just not have the air tube on good.

 

[manimal]

prolly air tube leak like pac said. Really common gotta get it nice an snug


Make sure the Blue clip is really on there as well.

 

[njmodi]

Sounds like a vacuum leak or intake leak past the MAF, unplugged connector, etc. nothing to do with the air filter.

If everything is in place/connected/snug then you may have bumped and cracked a hose that was getting brittle with age.

 

[phucheneh]

IIRC there is a PCV tube that is plastic. I would be looking at that.

 

[MiataNC]

Check all of the plastic tubing and hoses from the airbox to the throttle body.

Based on the age and mileage it is very likely that something cracked or split and is causing a vacuum leak. It may have pre-existed and the dirty filter blocked enough air to hide the vacuum leak until the new filter flowed more air.