missing and backfire through air cleaner

1999 FORD RANGER
140,000 MILES • 3.0L • V6 • 2WD • AUTOMATIC
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AXLE62249
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  • 2 POSTS
no codes in ECM. back fires and misses. when driving gets worse the longer you drive. had at a shop could not figure it out. i installed new plugs wires coil pack and EGR. cleaned throttle body mass air flow, and idle control valve. no improvement.
Apr 23, 2017 at 2:44 PM
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HMAC300
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  • 48,601 POSTS
check for a vacuum leak then pull the valve covers off and check to see if broken springs, push rods or rockers. If you can start truck and take off plug wire one at a time to see if you can locate which cylinder is doing it. If it is going through air cleaner it is an intake valve.
Apr 23, 2017 at 4:06 PM
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AXLE62249
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  • 2 POSTS
Truck fires right up. Idles around 1000 rpm. Small exhaust leak on drivers side at manifold. Just noticed fan turns a little stiff.
Apr 23, 2017 at 5:19 PM
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HMAC300
  • CERTIFIED EXPERT
  • 48,601 POSTS
this has noting to do with a backfire, try what I said in first reply
Apr 24, 2017 at 6:11 AM