1999 Mercury Cougar misfires

240,000 MILES • 6 CYL • FWD • MANUAL
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WIWCHAR
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  • 1 POST
my car was misfiring. i put a code reader on and found out the it was misfiring in cylinder 4. i figured it was a botu time to do a tune up so i went out and purchased 6 new spark plugs and a new set of wires. i hooked them up and the engine didnt seem to run very well. not much power and hesitant. i ran the code reader and was getting nothing. then when i parked the car and let it sit idleing come codes came up. no longer was cylinder 4 misfiring but now cylinders 5 and 6 are misfiring not only that but some smoke was coming out of the back side of the engine underneath the ignition coil. im not sure exactly where it came from but now it sounds like a knocking sound in my exhaust. any suggestions?????
Jun 2, 2009 at 4:48 PM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Engine misfiring can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.
Jun 2, 2009 at 9:22 PM
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