Engine Misfire On 03 Mach 1 - No Check Engine Light
03-25-2017, 12:53 AM
#1
Engine Misfire On 03 Mach 1 - No Check Engine Light
Hello!
I recently made a post about trying to figure out why my 03 Mach 1's engine is shaking, lack of acceleration, and clunking noise when driving.
I got the car back after about 2 weeks of it sitting and It was running great until about an hour of driving, the engine started to feel like it was bogging in a way. Then when I stopped at the light, I noticed excessive shaking from the engine. At first those were the only problems, but the more i've driven it, a clunking/banging noise has started to occur that becomes slower when I slow down and faster when I speed up obviously. The shaking also happens at idle, and while driving.
At first I suspected the motor mounts, but then as I listened closer to the car I noticed that the idle sounded much different. I took it to my local shop and just by listening they told me they were sure it was a misfire, and that that could cause the shaking and clunking and lack of power.
I recently installed (about 4 months ago) brand new spark plugs on all 8 cylinders, so I do not think its the plugs themselves. So I bought 2 ignition coils and swapped them out one by one with each coil to test if a coil was bad, and every time I started the car after swapping a coil, the engine shaking continued. I also noticed while swapping the coils that 2-3 of the wires that hook up to the coils did not "click" in to place. They slid right on, but they did not click like I said. I really don't see this causing a misfire since there is still a solid connection, but I would like any and all input.
Another thing to note is that I do not have a check engine light on, and I read the codes with our tuner and had no codes. That is where I am confused, because to me it definitely sounds like a misfire, and all 3 mechanics at the shop agreed on that as well. I would like any and all input on what you guys think this could be, whether you believe its a misfire or not.
A few other things is that a bit of white-ish smoke comes out the exhaust when I rev the car, and also there is occasionally some hesitation when I rev up the engine when its not in gear. Could this be injectors, fuel pump, or even a blown head gasket? I did notice that the coolant level was low, but other than that I didn't see any indications of a blown head gasket.
Thanks so much for reading, and let me know what you think!
I recently made a post about trying to figure out why my 03 Mach 1's engine is shaking, lack of acceleration, and clunking noise when driving.
I got the car back after about 2 weeks of it sitting and It was running great until about an hour of driving, the engine started to feel like it was bogging in a way. Then when I stopped at the light, I noticed excessive shaking from the engine. At first those were the only problems, but the more i've driven it, a clunking/banging noise has started to occur that becomes slower when I slow down and faster when I speed up obviously. The shaking also happens at idle, and while driving.
At first I suspected the motor mounts, but then as I listened closer to the car I noticed that the idle sounded much different. I took it to my local shop and just by listening they told me they were sure it was a misfire, and that that could cause the shaking and clunking and lack of power.
I recently installed (about 4 months ago) brand new spark plugs on all 8 cylinders, so I do not think its the plugs themselves. So I bought 2 ignition coils and swapped them out one by one with each coil to test if a coil was bad, and every time I started the car after swapping a coil, the engine shaking continued. I also noticed while swapping the coils that 2-3 of the wires that hook up to the coils did not "click" in to place. They slid right on, but they did not click like I said. I really don't see this causing a misfire since there is still a solid connection, but I would like any and all input.
Another thing to note is that I do not have a check engine light on, and I read the codes with our tuner and had no codes. That is where I am confused, because to me it definitely sounds like a misfire, and all 3 mechanics at the shop agreed on that as well. I would like any and all input on what you guys think this could be, whether you believe its a misfire or not.
A few other things is that a bit of white-ish smoke comes out the exhaust when I rev the car, and also there is occasionally some hesitation when I rev up the engine when its not in gear. Could this be injectors, fuel pump, or even a blown head gasket? I did notice that the coolant level was low, but other than that I didn't see any indications of a blown head gasket.
Thanks so much for reading, and let me know what you think!
03-26-2017, 04:53 PM
#3
2nd Gear Member
Join Date: Nov 2009
Location: Georgia
Posts: 176
I have a similar issue to yours on my '01 GT. No lights but definitely a misfire. I took it to a shop and they said one of the COPs had a tear in the rubber boot and oil was getting in there which negates the spark. They cleaned it out and it ran great, but romp down on it one time and that's all she wrote. They said it was on the #1 cylinder so I bought a new Motorcraft COP and plan to replace it soon. Can't say if that's the fix but my issue is very similar to yours and that's what they recommended. Sounds like you've tried replacing the COPs and that didn't do it.
03-28-2017, 07:53 AM
#4
2nd Gear Member
Join Date: Nov 2009
Location: Georgia
Posts: 176
I pulled the coil pack this morning and sure enough there's a bunch of clean oil sitting all around the spark plug. My guess is either someone made a real mess when pouring the oil (mine is the #1 cylinder) or there's a valve cover gasket leak. My motor has almost 200k miles so I'm voting it's the latter.
Last edited by Gadgetech; 03-28-2017 at 07:57 AM.