Engine Performance problem
2004 Dodge Intrepid 6 cyl Two Wheel Drive Automatic 99800 miles
Hello. I have a 2004 Dodge Intrepid 2.7L V6 with 99800 mils. I was experiencing bad fuel economy and replaced the O2 sensors, Plugs, and Coils. After this I was experiencing a Check Engine light and rough engine performance when accellerating. At first I did the front O2 sensors and then realizied I needed to do the rear ones. After that the car still runs rough. My mechanic did a diagnosis and told me to have the ECM flashed and it should fix the problem. I did that and $100.00 later and 6 weeks, my car is still running rough. Dodge told me that I was having a code for a emissions leak and the upstream O2 sensor was reading high and they needed to diagnosis it again. I am about to take it back to Dodge but am unsure if this is covered by my extended warranty. Could I just have one Sensor that is bad and just needs to be replaced?
P0300 -Normally caused by vacuum leak and bad fuel
Engine misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.
December, 15, 2009 AT 6:17 PM
Thanks for the prompt response.
The technician said that he heard a leak near the Exhaust manifold possibly. I am just confused because it seems the car ran fine except for the bad gas mileage. To replace the manifold, typically is the cost expensive? I was wondering if it was under $500. I am guessing I am going to have to go to the dealer and run it on the computer for $110. And get the diagnosis.