slideways Posted Friday at 02:30 PM Report Share Posted Friday at 02:30 PM My 2008 has been doing this for almost 10years now but its so consistent that i'd like to actually fix it at some point. At low rpm when lugging the engine or basically cruising in O/D at any time or in any gear it will thump in the floorboard which is most certainly a misfire. The great thing is it never throws codes for it. Years ago i replaced the plugs around 100k which cured the heavy symptoms. Then at some point around 150-175 i replaced all 6 coils/plugs. Around 190k it actually threw a misfire code for a bad injector which i changed. At 195k i had all injectors replaced when i had my water pump job done as PM. Car has also had the OSS/TSS sensors done in the transmission. Basically at 218k this vehicle has had all of the items done that should cause this problem and still misfires religiously with no codes. Does the PCM itself actually control spark to the point where it would be the last item to change? I have never "fried" a coil that would have damaged it and the problem has continued throughout the last 120k miles of this thing's life despite all these parts being changed. 1 Quote Link to comment Share on other sites More sharing options...
1004ron Posted Friday at 03:03 PM Report Share Posted Friday at 03:03 PM What are you using to read codes? What spark plugs are you using and where do you purchase them from? Quote Link to comment Share on other sites More sharing options...
fishx65 Posted Friday at 07:38 PM Report Share Posted Friday at 07:38 PM Usually a bad coil pack when misfiring under load. Quote Link to comment Share on other sites More sharing options...
Samurai Edge Posted Saturday at 02:46 PM Report Share Posted Saturday at 02:46 PM Bad coil pack or a bad coil pack connection. If the connector is not properly secured, it will definitely cause this issue. 23 hours ago, 1004ron said: What are you using to read codes? What spark plugs are you using and where do you purchase them from? These are also very pertinent questions. - Were the plugs purchased from an actual Ford dealer or an otherwise known trusted source? Sometimes you can get symptoms and not get a code because the symptom is so brief, it does not get identified by the code reader BUT use the wrong type or cheap code reader will be of no help 1 Quote Link to comment Share on other sites More sharing options...
slideways Posted Monday at 06:07 PM Author Report Share Posted Monday at 06:07 PM 100% OEM Motorcraft Plugs in both cases when i changed them before and more recently with the OEM coils. I only have a cheap code reader but like i said there are no codes and never has been except in the instance when i had the misfire caused by the bad injector which cleared when that was replaced. And then also replaced all others with OEM. I'd guess like you said its so intermittent that no codes presents itself. Quote Link to comment Share on other sites More sharing options...
1004ron Posted Monday at 08:24 PM Report Share Posted Monday at 08:24 PM (edited) On 7/24/2026 at 11:03 AM, 1004ron said: What are you using to read codes? What spark plugs are you using and where do you purchase them from? 2 hours ago, slideways said: 100% OEM Motorcraft Plugs Like these OEM plugs? Set of 6 OEM Motorcraft SP594 Ford CYFS12YRT3 Spark Plugs Replaces SP542 SP578 Edited Monday at 08:25 PM by 1004ron Quote Link to comment Share on other sites More sharing options...
slideways Posted 4 hours ago Author Report Share Posted 4 hours ago That link doesnt cover an 08 Edge but its been so long i cant recall. I didnt get them from ebay it seems according to my past purchases. Must have been RockAuto. They were in motorcraft boxes both times i did the plugs and also the coils were motorcraft. Quote Link to comment Share on other sites More sharing options...
1004ron Posted 1 hour ago Report Share Posted 1 hour ago If you're unsure of where the plugs were purchased then they're suspect in my opinion and would recommend they're replaced using ones bought from a reliable supplier such as RockAuto, and not eBay or Amazon. The knockoffs also come in Motorcraft boxes. 1 Quote Link to comment Share on other sites More sharing options...
Samurai Edge Posted 52 minutes ago Report Share Posted 52 minutes ago Yes, it typically will cost you more money but when you buy parts, make sure you are buying the real McCoy and not some cheap knock-off. Scammers selling cheap look-alike knock-offs are everywhere. Companies, like Amazon for one, may buy from their Buyer but that doesn't mean what they bought was real. Too many times a company's Buyer's instructions are to get the best price. Best price on what is the real question. Scammers are getting better at marking products to look just like the real thing. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.