How do I fix a 2000 Dodge Intrepid P301 (Cylinder 1 Misfiring) after changing the spark plugs and oil?

I have a 2000 Dodge Intrepid which shakes at idle in any gear (but less in Neutral) When I accelerate, the car struggles somewhat to get to speed. (mostly when on the highway and some car slows down and I have to accelerate to get back to speed) The engine light stays on when turn the car on, and blinks when I accelrate. The cruise control has to pull the accelerator all the way down to go up inclines. NOW--I change my oil, keep her full of gas and use STP gas treatment regularly. I changed the plugs and for 2 days, the engine light stayed off although she performed SLIGHTLY better than before the change. I am a do-it-yourself mechanic with some training and the HAYNES manual for my car. It may also be helpful to know that whatever is causing the shaking is also pulling on my battery. I can see my headlights dimming as it shakes and when I accelerate, my lights brighten as if I'm giving the power to them directly by pressing the gas. I don't want to lose this car, so please help. Any information is helpful, as I take what I know, add what I don't, listen to what I've learned and do what I can before paying thousands of dollars for someone to tell me it'll cost more to fix it.How do I fix a 2000 Dodge Intrepid P301 (Cylinder 1 Misfiring) after changing the spark plugs and oil?
You didn't state which engine you have, but they should be a coil over type ignition. I would first do a compression test on the #1 cylinder to make sure you don't have a valve problem. Next, try swapping the coil packs between cylinder #1 and another cylinder. If the fault moves with the coil pack, replace the coil pack. If not, then you may have an injector problem.





The check engine light (CEL) flashing indicates that the conditions are right to do damage to the catalytic converter. You are dumping unburned fuel into the exhaust from the misfiring cylinder.How do I fix a 2000 Dodge Intrepid P301 (Cylinder 1 Misfiring) after changing the spark plugs and oil?
i would have to agree with what the first guy said but i would like to add to that too....now this is a very unlikely problem but it's just another possibility.....your timing belt or chain (whichever it has) could be worn out....the timing belt or chain could very well be out of whack....like i said.....it's unlikely but in my 40 years of mechanics i have seen it happen.....but very very very rarely....especially with the description you gave....but don't rule it out.....