2003 Dodge Intrepid. Acceleration problems & engine light flashing

There are various ways the Check Engine light will act depending on the severity of the problem. The most serious is when it is flashing. That is very rare and means stop the engine right now before serious damage occurs to the catalytic converter. It is overheating due to excessive unburned fuel entering the exhaust system.

Anytime the Check Engine light turns on while driving, there will be a diagnostic fault code stored in the Engine Computer. Having that code read is the place to start. It will indicate the circuit or system with the problem, not necessarily the defective part. Many auto parts stores will read those codes for free. Don't put that off too long. If the problem doesn't act up again in the time you start the engine 50 times, the code(s) will erase automatically and that valuable information will be lost. Disconnecting the battery or running it dead will also cause the codes to erase.

Caradiodoc

Those codes are related to three different circuits so a logical place to start would be with the wiring harnesses and connectors. The first code means the signal wire for the left front oxygen sensor is shorted to voltage. The first suspect would be the harness fell down onto hot exhaust parts and melted to the feed wire for the O2 sensor heater. Next, use the scanner to view live sensor data and see what that O2 senor is reading for voltage. If it is above about one volt, start unplugging things to see what it takes to make the voltage go back down to normal.

Caradiodoc