2004 Mazda MPV running rough

Tiny
BRAKE LIGHT
  • MEMBER
  • 2004 MAZDA MPV
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 125 MILES
I have a 2004 Mazda mpv. The problem I'm having is that the car****** at times. Sometimes when driving and sometimes sitting still like at traffic lights. It has the resemblance of a vacuum problem. It gets worse when ac is turned on. Also when it"s changing gears the tach will rev higher. Has not had a check engine light come on. Any help would be great. Thanks, Chris
Wednesday, June 22nd, 2011 AT 2:32 AM

3 Replies

Tiny
SIXPACK SUBARU
  • MEMBER
  • 22 POSTS
This engine is known for coil issues. And they are NOT cheap. Best way to diagnose is by part substitution. Ie; replace them with known good coils. Bench testing coils, and/or ignition leads is not a sure-fire way to tell if they are faulty.
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Wednesday, June 22nd, 2011 AT 11:10 AM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Have the spark plugs checked as well.

As to the engine revving higher, check the transmission fluid level.
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Wednesday, June 22nd, 2011 AT 11:46 AM
Tiny
BRAKE LIGHT
  • MEMBER
  • 2 POSTS
Great advice guys. I replaced the ignition coils and so far so good. Removing and replacing plenum assembly was tough but was managable. This seems to have corrected the tach revving higher as well. Thanks Again, Chris
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Monday, July 4th, 2011 AT 4:33 PM

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