Cincy03GT

Hello,

I own a 2003 Mustang GT which was running strong until last week. On the way to work my car sorta cut out during acceleration and jerked a little bit. Shortly after, all of my dashboard lights flashed intermittently for a brief second. As I pulled in the garage my car died as I was putting my top up.

I replaced the battery and that solved the weak battery symptoms. Immediately after changing the battery. I pulled out onto the road and accelerated. My car was sputtering/jerking/cutting out until around 3500 rpm in all gears. The exhaust sounds muffled when this happens. I replaced the spark plugs and dumped a bottle of Techron into the tank. Symptoms were still present but much less noticeable.

Today, I unplugged the injection valves one at a time listening for a change in Rpm.. telling me if the engine is dependent on the plug. If there was no change in RPM, the plug is bad. After securely reconnecting all injection valves (Which all plugs 'passed' the test), I ran an errand, and the bogging/shuttering/cutting out was worse than ever and extremely noticeable in all gears. It took like 15-20 seconds to reach 35mph.

Do you think its the injection valves? Any other ideas? Any help is greatly appreciated. This is driving me crazy how poorly its driving right now.

LuvThis2kGT

I had problems with my '00 GT that sounded similar, straining to get to speed, rough idle, sluggish up hills. Turned out one of the coil packs went bad. Some of my research found guys were washing their engines and were getting water down in the spark plug bays and were ruining coils in the process.

uberstang1

Ensure the connection on the battery aren't loose, take the car to autozone and have them do a starting/charging test on it just to rule out a bad alternator which in some cases causes goofy problems with the COPS when bad. After that I would start looking at the COPS.