I just got a strange misfire today. I had a fouled plug with my original plugs and drove it hard and that disappeared. This is a recent set of platinums that were installed. I also had a set of Accel COPs put in at the same time. Maybe have 2000 miles on everything. It doesn't throw a code yet but you can feel and hear one cylinder isn't up to snuff. It doesn't show on the vacuum guage as anything burnt like a valve. It's rather a steady reading with the idle RPM not varying more than 10 rpm either side of 580. To me it feels like something on the verge of quitting functioning. Any ideas?

 

What kind of plugs did you put in? and a few guys on here have had probs with accel COPS...not sure if it was Accel COPS or coil packs but i know one of the 2 F-150's dont work well.

 

I had platinum motorcraft replacements as those engines are picky. The COPs are brand new and I should even be able to get my money back. It doesn't feel failed what ever it is.just not up to snuff.

 

Did the engine get wet? did you use lots of dielectric grease? The for dealer can stress test it and move the coil. Might be you got a bad one.

 

The engine never sees water. I just had all the hoses and belts replaced. I can't work on my truck yet so I had a local highly reputed garage change them. The stealership is where you go for new cars and free parts. No more no less.

 

I found the problem finally. It was #3 COP. I took resistance readings from the contact point spring for the spark plug to either of the input terminals. Accel is a reading of 6.3 on the 200k scale and compared to a stocker of 5.2-5.6. The third coil I replaced read 4.3 and I figured that was the culprit before I started the engine to try it. This reading confirms why it wasn't a complete misfire. I'm just still used to complete misfires from single coil setups. I'm not at all a chebie fan but the coil per cylinder setup is ez as far as troubleshooting. Thanx to all for the inputs.

 

ACCEL COPs are worthless junk. Three have failed in 6 months. The first within a month of install, it completely shorted out sending the engine into safe mode. The other two failed within the last week, producing a misfire during acceleration at 1300-2000 rpm. The stock COPs are going back in tomorrow.

2006 Lariat F150 Screw
3.55 gears
22" w 305-45-22 Continental
Extang Fultilt Tonnoue
Flitch Fuel Catalyst
Royal Purple Lubricants
Corsa Sport Exhaust
2" Eibach Shakle Kit
Troyer Elec cooling fan
MAD Fan Controller
K&N Cold Air Intake 632556
SCT LiveWire Tuner Troyer Tune
Dynatech headers
Accel COP
Granetelli COP connectors