Three problems related to engine and engine cooling have been reported for the 2004 Ford Mustang. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Ford Mustang based on all problems reported for the 2004 Mustang.
The spark plugs have a tendency to blow out. An explosion makes the plug strip the threads and do damage to the head. There is also potential for fire as fuel vapor is then release directly into the engine compartment.
On multiple occasions the number five spark plug keeps blowing out of the head. The car has motorcraft spark plugs and are torqued to the factory specifications. While looking into the problem online I found out that im not the only person having this problem. The crazy thing is that its is only happening with the number five plug.
I own a 2004 Mustang with a 4. 6 dohc engine. Last night the spark plug blew out of the head. The head now needs to be repaired by using a helicoil or something similar. This is a huge problem with the Ford modular engines, caused by poor design. At least 75% of the people I know who own Fords with modular engines have had this problem.