1999 Mazda 626 Idles rough and stalls when in park

Tiny
CRACKCORN
  • MEMBER
  • 1999 MAZDA 626
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 120,000 MILES
When my 99 mazda 626 is at operating temp it idles rough and stalls sometimes in park, when at a stop light in drive it idles better. When I unplug the mass air flow sensor it idles fine! Should I replace the maf sensor? Some one told me it could be the air temp sensor in the airbox. Replaced the plugs, pcv valve and hoses.
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Sunday, March 28th, 2010 AT 9:21 AM

12 Replies

Tiny
LEGITIMATE007
  • EXPERT
Yes, good observation, with the mass airflow sensor, also you should have a check engine light on, no? If so, just have it scanned at autozone, it will reinforce your observation, and if not, it will atleast give us something definite to go on, just jot the codes down and bring them to me for further diagnosis, but very good, on your finding.
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Sunday, March 28th, 2010 AT 9:22 PM
Tiny
CRACKCORN
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I replaced the mass air flow sensor and still the same thing! I'm not sure what is is. If you unplug the maf sensor still it runs better! Could it be a vacuunm leak?
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Tuesday, April 6th, 2010 AT 4:49 PM
Tiny
LEGITIMATE007
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Yes it could be a vacuum leak amongst several other possibilities, if there is a check engine light on, bring it to autozone or your local parts store and have it scanned, it will make it so much easier and narrow the possibilities down, other possibilities, can be the egr valve, the idle air control valve, the iat(idle air control valve) that sensor in the air box.
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Wednesday, April 7th, 2010 AT 5:50 AM
Tiny
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No check engine light on. Where should I start should I try to clean the iac valve? Where is the egr valve located?
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Saturday, April 10th, 2010 AT 3:21 PM
Tiny
LEGITIMATE007
  • EXPERT
I would start there, and clean the throttle body if you havent already. I have a diagram, I am assuming this is the 2.0 if not then let me know. Also the hose/accordian hose that is connected from the airbox to the throttle body look at it really well and see if there are any cracks or holes in it, this will cause you some problems.
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Saturday, April 10th, 2010 AT 5:59 PM
Tiny
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http://www.2carpros.com/forum/automotive_pictures/88091_iac_626_20_1.jpg

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+1
Saturday, April 10th, 2010 AT 6:00 PM
Tiny
LEGITIMATE007
  • EXPERT
http://www.2carpros.com/how_to/how_to_tune_up.htm
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Saturday, April 10th, 2010 AT 6:02 PM
Tiny
CRACKCORN
  • MEMBER
I cleaned the iac valve and the egr valve. The egr valve was filthy! I put a new throttle body gasket on and started t up and went for a 20 minute drive. It idled great!Plus the exhaust wasn't making a puffing sound anymore. When I was driving it was sputtering a little bit. Is this because the computer needs to reset the settings?
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Thursday, April 15th, 2010 AT 12:05 PM
Tiny
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NEVERMIND! I took it to the store and wouldn't you know. At the stop light it started loping again, and I floored it and it backfired a little. The popping in the exhaust is back. Does a mechanic do a reliable vacuum test?
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Thursday, April 15th, 2010 AT 4:57 PM
Tiny
LEGITIMATE007
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Yes, I know your frustrated, but it will get fixed, its not as easy as some people think. Check the mapp sensor, also see if the accordian has any cracks in it. And of course the catalytic, I dont remember if you said you had that looked at
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Friday, April 16th, 2010 AT 10:40 AM
Tiny
CRACKCORN
  • MEMBER
Thanks for your help! I broke down and got it checked for a vacuum leak, and the intake manifold gasket and the injector orings needs replacing. He is charging me 300 for both things.A coouple of garage mechanics quoted me at 200 plus parts. Do you think this is a fair price?I guess its worth it to get it off my mind!Thanks again.
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Tuesday, April 20th, 2010 AT 5:28 PM
Tiny
LEGITIMATE007
  • EXPERT
Yeah, thats a good price, it is kinda painstaking too, to get these done, so rest assured your good to go. Awesome, keep me posted as how your vehicle is doing afterward, we are always here for ya.
Jody
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Wednesday, April 21st, 2010 AT 8:22 AM

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