Hey guys. I drive a 2007 V6 Mustang. I did a quick check and didn't see anything specific for my issue. Last night I did an oil change and replaced the spark plugs and wires. everything was fine, I drive to work today and as im driving i notice a little rumbling when i hit about 50mph. Feels like I'm driving off-road when it happens. I get further down the road and and notice that the rumbling only happens when trying to accelerate. gentle pressure on the gas and very slow acceleration was ok. Then i get to work and it wont start. I hear clicking, some of which sounds to come from the under the hood fuse box but there is no turn over like the battery is dead but that is not the problem. I'm pretty sure the starter needs to be replaced but if you guys have any ideas as to what the rumbling is that'd be much appreciated

 

Josh, when reading your post for the first time, when you mentioned "Rumbling at about 50 mph," I immediately thought "driveshaft." And that might be a separate problem. But, the driveshaft wouldn't cause the engine not to start. If the battery is no longer "fully charged" could you have accidently disconnected a wire in your charging system while changing the plugs and wires??? Driving to work may have taken long enough to discharge the battery. Check all your wiring for a loose or disconnected wire.

 

The center bearing of the stock two-piece driveshaft is probably failing.

Check the contacts between the battery cables and posts for looseness or corrosion.

 

When you replaced the wires you might have mixed up the pattern. It is very easy to do with the 4.0 coil. It is in numerical order on one side, but not the other. The car will start and run with them mixed up because of the waste spark system, but you will get issues as you described.

So look at the coil and trace your wires to make sure you didn't mix things up.