02maz626

Idles rough when stopped then stalls

6 posts in this topic

I have a 2002 mazda 626 2.0 l4

When idling at a stop sign or red light, it shakes and runs rough and sometimes stalls. Putting it in neutral, it will go back to a smooth idle. Any thoughts? I have only had the vehicle for about 4 months, so i don't know of how well this car has been maintained.

I have replaced the spark plugs, oil change with full synthetic, I have a new Air Intake Man Gasket and Throttle Body gasket that I will be replacing later this evening. Maybe the MAF?

The codes are saying misfire in cylinder 1 & 3. Also saying system too lean?

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How many miles on it?

If you're getting misfires, engine codes, and a lean condition - and you've verified your misfires are not spark related - it might be time for a compression test. It's free, and that way, you can make sure the innards are healthy before being nickeled and dimed to death replacing other bits. You could run injector cleaner thru a tank of gas just on the hope there's a dirty injector, but it never turns out to be that simple, at least not in my experience.

Anyway, you should be able to get a compression tester for a free rental period from various auto parts stores, & the actual test itself takes like 10 or 15 minutes. There's lots of videos out there on how to do it. And it's kinda fun. But all this stuff is fun, right?

If your compression is low, then there's various steps after that to figure out exactly why.

If your compression is normal, then that justifies exploring fuel delivery problems, & spending money on things like injector cleaner agents.

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Thanks for the reply @smuryofI'm going to look into a compression test today. Theres about 180K on the car. Ive done the injector cleaner. I wasn't that lucky. Lol. Im hoping it will be something simple. I have the air intake man gasket, I will be attempting to replace today. So let's hope for the best

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How did your compression test go?

Also check the timing - harbor freight sells a timing light for like $30 or so, and it only takes a few minutes to do. My timing was off by 10deg. and it made a HUGE difference in engine performance. At a $30 investment, it's well worth it and a mandatory tool to have on hand.

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@smuryof, the compression was fine. I killed my starter trying to crank it originally, so I replaced it. Then found out my fuel pump was bad. Replaced that over the weekend along with the manifold gasket. hile removing my fuel rail,  to replace the gasket, I found a bad seal around my injector. So I spent like $5 for a seal, no more idling rough or anything. All because of a seal

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Yea sometimes it's simple things that stay hidden till the end of a big job. Well I'm glad that's all it was!

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