1996 Mazda Protege Rough Idling when engine is warm

74MADURO

MEMBER
1996 MAZDA PROTEGE
4 CYL
2WD
AUTOMATIC
220,000 MILES

The rough idling occurs when the engine is warm. It doesn't matter if the transmission is in gear or neutral. The RPMs need to be above 1000 to avoid the roughness. I've cleaned the throttle body, replaced plugs, wires, rotar, cap, had fuel injectors checked. It is extremely high mileage, and I am going to get rid of it soon enough, but I still would like to know what is causing this issue. Thanks

8 Replies

RACEFAN966

MECHANIC
5,029 POSTS

Is the check engine light on? If so find a local parts store and have do a free scan and get the codes. Do you have a digital multi meter? Get back to me and we go from there.

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Thursday, February 19th, 2009 AT 11:20 AM

74MADURO

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5 POSTS

No. The CE lite is not on, and I know it works.

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Thursday, February 19th, 2009 AT 11:23 AM

RACEFAN966

MECHANIC
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OK have you tested the coil pack? Do you have a digital multi meter so we can test it and see what it is doing. Get back to me

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Friday, February 20th, 2009 AT 10:16 AM

74MADURO

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5 POSTS

I don't know where that is on my car (what it looks like exactly), and how do I measure it properly with an OHM meter? And if it's a problem with the spark, would that give me trouble all of the time, not just when the car is running at normal opp temp?

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Friday, February 20th, 2009 AT 10:28 AM

RACEFAN966

MECHANIC
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No not alway's as a coil can work fine when it cold then when it gets hot it will start to fail not uncomin. Now do you have a digital multi meter? If so then I will look up the test and tell you how to find out if it is bad. It looks like your coil is part of the distributor. I also need to know which engine do you have the 1.5 or the 1.8 DOHC. Get back to me.