Misfiring Under Load.

birel21y

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I have been having this problem for a couple weeks now. Ever since i changed my plus, wires, cap and rotor, o2 sensors, and cleaned my MAF. It seems like an ignition problem, like its on and off running on 7 cylinders only under load, and missing. and it will do it more often when the engine is cold, or when i first start it up, and like i said, its only under load. Could this be a cracked spark plug? I was runing NGK Iridiums, but now im running the regular v-power plugs. Do i need Iridiums with my Crane Cams Fireball Ignition? There seems to be a high amount of resistance through the cap and rotor. they only have around 100 miles on them, and the brass tabs inside the cap are turning silver and black, and alll the conections look burnt.

Heres the mods.cobra cam, ported / polished non smog Gt40 heads Trick flow valve springs hardened push rods, trick flow valve covers, 1" phenomic spacer matched upper / lower cobra intake, 75mm bbk throttle body, bbk intake, optima red top battery, ported mass air, underdrive pulleys, no air pump / egr, findanza 13lb. billet aluminum flywheel, centerforce dual friction clutch, 2004 mach 1 rear end with 355:1 gears, 180* thermostat. EXHAUST- bbk eaqual length shorty headers, bbk x-pipe, borla xr-1 cat-back. BRAKES / SUSPENSION- 10th anvrsy. red powdercoated cobra brakes, 13" vented / slotted / cross-drilled brembo rotors, steel braded brake lines, Tokico shocks all way around, eibach progressive rate springs, bbk upper / lower control arms, polyurathane rack bushings, a-arm bushings, transmission mount, subframe connectors. INTERIOR- 2004 Mach 1 seats / gauge bezel / Airbags / panels / center consol / shifter handle/ carpet / dash/ shifter bezel...ect, Autometer water temp and lean/rich gauges on A-piller mach 460 sound system, Windshield tint strip, 20% tint side windows, 5% on back 3 windows, short throw shifter. EXTERIOR- 17" mach 1 rims, 2004 mach 1 flat black wing, black trimmed taillights, cobra package, grillecraft silver grille.

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purplehaze

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check your coil first.swap coils before moving on to anything else. this is the easiest. good luck
 
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As mentioned above. These are the possibilities.

Burnt spark plug wires.

Bad coil.

Firing order is wrong.

Your distributor going out.

I had similar problem when i added MSD digital-6. I didnt know MSD coil was going bad. It felt like misfiring. Changed the coil. Problem solved.

Spark plug boot was cracked(ford racing) 3 and 4. changed those problem solved.

Something about stator in distributor. Got a new distributor problem solved.

"No" you do not need to run iridium spark plugs for your ignition.

I hope you got your iridium for free some how because there is no way i am spending over 100 bucks on spark plugs...WOW.

Aren't they supposed to last like over 100K?
 
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birel21y

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Problem solved guys.... thanks for the help. It was just a cracked spark plug.
 

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