2005 Ford Freestar • 3.9L 6 cylinder 2WD Automatic • 85,000 miles

Emission light came on while driving. Blinked for while and goes off. Engine speed down graded during bilking of emission light. Felt vibration from engine. After minute so, emission light goes off and vehicle speed became normal with power and no vibration felt?
Car help786
February 17, 2014.

The blinking of the light indicates that what is happening could damage the catalytic converter, and it probably a miss-fire. Do not drive it any more than you have to. Try to get the code or codes read and post them here for us.

Feb 17, 2014.
The flashing light indicates the most serious of conditions and you're supposed to stop the engine as soon as possible. Don't keep on driving. Too much raw fuel is going into the exhaust system and is going to overheat and damage the catalytic converter.

The engine vibration is due to a misfire. That will send unburned fuel and air into the exhaust system and will cause that overheating of the catalyst. The Engine Computer detected that misfire condition and set a diagnostic fault code that will indicate which cylinder was responsible. It is important now to not disconnect the battery or let it run dead. Doing so will erase that code, then that valuable information will be lost. Many auto parts stores will read the codes for you for free. It's important to understand those codes never say to replace parts or that they're bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. With the exact code number we can figure out where to start.

Feb 17, 2014.