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1998 GT supercharged, random misfire - dropping cylinder? No codes

  • Thread starter Thread starter thebuckaman
  • Start date Start date Aug 17, 2022
  • Tags Tags
    4.6 2v misfire
T

thebuckaman

Member
Jul 10, 2006
37
0
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Central, IL
Aug 17, 2022
#1
  • Aug 17, 2022
  • #1
Hello,

I have a 1998 Mustang GT that has a vortech V1 with FMU. I bought the car 2 years ago (mods were already on the car) and did a bunch of maintenance at that time.

10w30 mobil 1 synthetic with FL1A
New coolant
New brake fluid
New PS fluid
New trans fluid
New rear diff fluid
New fuel filter
New plugs (Autolite 103 with .035" gap)
New ford racing wires 9mm
New screamin demon coils
new TPS
cleaned the MAF
New K&N filter
New PCV
Replaced a bad fuel injector connector
New air intake temp sensor

Car ran well after I did all of that and was fun to drive. I have only put about 1k miles on the car since the maintenance was done.

Then, this month it started with a random string of misfiring. Would drive fine and then randomly drag a cylinder/lose power. It would randomly "fix" itself and run fine, then randomly start missing again. I have checked the wires for crossing/arcing in the dark in my garage (sprayed mist of water too). Nothing showing. I tested the coils and they tested out fine. I removed the plugs and took pictures of them (attached). I cleaned the TB (wasnt too bad). Fuel pressure at rails seems to stay consistent at 38ish lbs. I have checked each of the injectors by removing the connector of each while idling and each one i unplugged, made it run worse. Vacuum seems consistent on my boost gauge and I don't see any bad or damaged vac hoses. My A/F reads lean when it is misfiring and normal when it resolves.

Any ideas on what else to check? My scanner shows no codes either. I am stumped at this point. Any help would be appreciated. Thanks


 
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