Rough idle and missing

2005 FORD MUSTANG
220,000 MILES • 4.0L • V6 • AUTOMATIC
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KASEY HAZEL
  • MEMBER
  • 1 POST
I was recently having issues with my car starting to idle rough and miss really bad after I had started it, turned it off and started again. We replace the spark plugs and wires. Once that was done it idled rough and missed the entire time it was running. So, we also replaced the coil pack and I did a cleaning on the throttle body and MAF sensor. It got a lot better after that but I can still feel it missing. Does anyone have any info or tips on figuring out the cause? Any help is appreciated. Thank you!
Nov 19, 2019 at 5:28 PM
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KASEKENNY
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 18,907 POSTS
This could be a couple things. If this is felt during idle then it could be an idle air control valve. This is responsible for allowing air in during idle operation. The other possible cause is a fuel delivery issue. I would recommend testing fuel pressure when you feel this and see if it is dropping at all.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let's measure the fuel pressure and go from there.
Nov 20, 2019 at 4:42 PM
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