COP Misfire Question
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COP Misfire Question
I have a 2003 Ford F150 Super Crew with a 4.6 V8 engine. The truck has 145,000 mile on it. About 3 weeks ago the truck began to miss/cylinder Misfire and check engine light comes on. So I take it by a local AutoZone to have the code read. They tell me its saying Faulty engine Coils. But would not say which specific ones were not working. My 2003 Ford has Coil on Plug. So I decided to change the spark plugs and all 8 Coil on plugs. After Installing the Spark Plug and COP. I dove the car. It now Miss fired worse than before. I took it by a Napa Auto parts store and they checked it. It is now showing misfires in all 8 coils. In researching I realized I had not put on anti-seize on the spark plug and I had not put dielectric grease on the inside of the COP. So the next day I remove the COP and Spark plugs. Rechecked the spark plugs for spark plug gaps. Made minor adjustments to the gap using different gap tool then I had previous day. I then applied anti-seize and dielectric grease to the COP. I then reinstalled. I dove the Vehicle about 10 miles. Truck ran great no missing/misfires. Then I pulled in drive way and let it idle. It started missing and service engine light comes on. So next morning I dive about 20 miles to Napa. While driving I noticed when driving about 70mph on cruse it did not miss unitl it accelerated on some slight inclines. But not near as bad as it had been. When at Napa it still show trouble code for all 8 Coils. He this time cleared code in computer. I drove back 20 miles. Ran great very few misfires. But when I slowed down to idle it started running ruff and miss firing again and check engine light came back on. I then drove another 60 miles with very few misfires only slightly on inclines. I had another auto parts store check it. They were getting same Ignition could codes on all 8 coils. I drove back with very few misfires. But still runs ruff when Idle.
Long description what is going on. But can anyone give me insight on what to do next to see what’s going on? I’ve read on internet were some have had to change the Pigtail connector to fix the problem. Should this be my next step?
Long description what is going on. But can anyone give me insight on what to do next to see what’s going on? I’ve read on internet were some have had to change the Pigtail connector to fix the problem. Should this be my next step?
