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1999 Mazda 626 Rough idle in drive

Replaced the idle air solenoid and the car still vibrates in drive when at the light, etc… Engine mounts were replaced though I am sure that isn’t relevant. Anything I can look for?

Did you put in aftermarket motor mounts?

Are you sure it’s not misfiring?

Might want to hook up a scanner and check it out

Was this meant to be a reply to an existing thread or something?

Sorry I did not see these replies sooner. Yes, aftermarket motor mounts and I don’t believe it’s misfiring though I will check codes. There was no existing thread, I started one.

Did you clean the idle air control valve and MAF sensor!

No …I will check and clean as well…Thanks!

Can you advise which is the MAF sensor? I know where the idle air control valve is on this '99 Mazda 626 LX

The MAF sensor is normally inline in the main intake tract between the air filter and throttle body. The important “guts” of the thing for cleaning purposes are two tiny little think wires.

This should come in handy:

Awesome! Tomorrows Project!

Thank you…

Fuel injector cleaner can sometimes help rough idle problems. A shop would probably recommend to bring all the routine maintenance up to date and do a few tests to eliminate other possible causes first.

Yea I can understand the cleaner though there isn’t a good shop anywhere in South Florida which is why I am doing all of the work. You don’t bring a '99 626 up to date on maintenance which would cost roughly the value of the car.

It depends. What routine maintenance suggested in the owner’s manual is currently behind schedule?

Any idea what this screw is and where I get this tool to get at the filament for the MAF? From the prev viseo I was sent to look at it looks easy until I get to this issue??

I am also using aftermarket Motor mounts since they were CHEAP! I understand that the front mount should be factory since that one is where I get most of the unwanted vibration or should they all be OEM.

You just need a torx bit. You can pick them up pretty much anyplace that sells tools. I would just get a set. You can buy them in “screwdriver” form, or to fit on sockets or as bits that you’d insert into a 1/4" hex like you would any screwdriver bit.

I have Torx though these have holes in the center…I will check Harbor Freight.


The ones with holes are just “security” bits. Some torx heads are made with a peg in the center - I believe a form of “tamper-proofing.” If you have security bits, they work either way. I don’t see a peg in the middle of the one in your pic, so I assume you’re saying you HAVE security bits, rather than that you need them. As such, the ones you have will be fine.

So I bought the security torx tool set, checked the MAF and it was clean (had lunch off it clean). Removing the elect harness from it showed it appears to be working when connected.

Checked the idle air control valve (replaced this a year ago), and it was clean. Same R&R with electrical conn indicates it appears to be doing it’s job.

Still have a vibration when in park or drive. When I turn the air off or on, the RPM dips and then goes back to the same RPM, which is just below the 0.5 mark on the tach.

There is a solenoid of some sort on the side of the air cleaner before the MAF which when I disconnect and reconnect nothing happens.

Any suggestions will be greatly appreciated.

Actually the idle is just below .7 after I adjusted the IAC screw counterclockwise.