[03SonicBoom]

I was leaving to go on a trip and my car starts shaking and the CEL comes on. AutoZone diagnosed it as a Cylinder 8 miss fire.

All my work on engines has been on pushrod engines and these mod motors look way different. I'm just trying to replace the spark plug and the cap (or whatever that's called). From looking at the engine, it looks like the plugs are right next to the injectors. It also looks like the coil packs are covered by the fuel rail. Is this correct or am I completely off?

If someone could post help on how to get the new plug in I would appreciate it. Normally I would just take it apart until I get to it. But, we're taking my buddies car this weekend and leaving the Stang in the garage. I figured I would post this and see what responses I get so I can work on it Sunday.

Any help would be much appreciated. Please, help out a n00b to the mod motor.

[HMUSN]

you don't have to remove the fuel rail to get to the plugs. it's just a tight fit is all. you know where the spark plg boots are on a fox? same deal with the the mod motors. just pull up on the coil pack ( basically like a boot with a box/electrical connection on it) and the plugs are directly underneath.

[Imran]

change your coil pack for cylinder 8. My car was misfiring like a porn star w/ erectile dysfunction, and i had to replace 4 coils

EDIT: It's not necessarily your coil pack, but i'd replace it anyways just to see.

[4.6LMadness]

dont replace them first. Try swapping them out and see if the miss follows that coil.

[03SonicBoom]

I got it changed and still have the problem.

I changed number 8 spark plug with a new one (gaped to 0.054). Drove the car and still had the CEL on. Here's some pictures of the original plug (ignore the sand, I dropped it on the floor).



I disconnected the coil pack and cap from cylinders 7 and 8 and switched them. I switch everything from the wire connector to the part the connects to the spark plug. I was hoping the misfire would jump to cylinder 7 when it was scanned again.

I got it scanned again and it remained on cylinder 8. So, I'm led to believe that it's not the plug and not the coil pack. The only thing I can think of would be the injector. Anyone have any better ideas on what it could be or second my idea on the injector?

[4.6LMadness]

it might be your COP, swap it with another one and see if the miss follows it.

[Smoking mustang]

Check your intake gasket for it leaking coolant ,it might be leaking coolant into that cylinder and causing the misfire,I have seen this on many mustangs and in the morning you get a bent rod if your not careful,coolant leaks overnight and fills cylinder with coolant and BAM Hydro Lock !!!!!!!

[03SonicBoom]

Originally Posted by 4.6LMadness it might be your COP, swap it with another one and see if the miss follows it.

COP is Coil over Plug? On cylinder 7 and 8 I switched everything from the wire connector to the plug and it stayed on cylinder 8.

Originally Posted by Smoking mustang Check your intake gasket for it leaking coolant ,it might be leaking coolant into that cylinder and causing the misfire,I have seen this on many mustangs and in the morning you get a bent rod if your not careful,coolant leaks overnight and fills cylinder with coolant and BAM Hydro Lock !!!!!!!

How likely is it that it would be something like that? The car only has 50k miles on it and has never been driven hard. I'm really hoping that it's something simple like an injector. I have a friend who's a mechanic at the Ford dealership and I'm taking it there at 1 for them to diagnose it. I'll update once I figure it out and get it fixed.

[03SonicBoom]

Well, I got it all fixed here. The problem was the fuel injector. Replaced it and now it runs perfect.