I have a 2006 Pacifica FWD. It started running really rough last week. 112,000 miles. i purchase a handheld OBD II scanner. It threw two Codes. P0301 (Cylinder #1 misfire) and P2097 (Post Catalyst Fuel Trim System Too Rich Bank 1). i have listen to every shade tree maechanic until i've replaced just about every sensor. They include: Air charge temp, EGR valve, MAP Sensor, Throttle Position Sensor, and the O2 sensor in the Catalytic convertor, replaced all the spark plugs, replaced the coil on #1 and #2 cylinders, new fuel injector on #1 cylinder. i have even drained the fuel out of the tank and filled it full of 89 octane. I am pulling my hair out. I erase the codes and they still come on after driving for about 15 miles. It is "sucking" down the gas. it's probably getting about 8 to 9 miles a gallon. CAN ANYONE HELP and lead me in the right direction?

 

look at mechanical engine issue like compression or valve issue
possible pcm and or wire issue

 

You will not believe what it turned out to be! I checked the compression last night (at least on bank 1 the ones i could get to without pulling the intake manifold off). all three of these cylinders had almost the same compression (around 115psi), however when i checked the compression, of course i had to remove the new spark plugs when i put them back in i must have mixed them up putting them back in the cylinders. the mis fire code moved from #1 to #5!!! who would have guessed that a new spark plug (Bosch Platinum Plus) woud have caused it. i dug out the old OE plugs from the trash can and put one back in, just drove 30 miles to work and no issues!

Have you ever seen a $1000. spark plug? i now have one!!!

 

use only champion spark plugs not bosh