I have a 2000 Honda Acoord Ex that began to run very rough when cold. After warming up it seemed fine. Now the car runs rough whether hot or cold. The car only has 23,000 miles on it. Any ideas? The cap, rotor, and wires all appear to be good.
Check the mass airflow sensor (MAF) and idle air control valve (IAC). Sometimes the MAF just needs cleaning. You might also check the spark plugs, as those might be original with such few miles.
Only about 2,000 miles per year on this car? That low of mileage can gum up the insides of an engine over this length of time. So what would gum up the worst? hmmm … first thing probably is check the egr, make sure it isn’t sticking partially open.
Try a 3M Fuel System Tune-Up Kit.
Yes, this car is rarely driven which is why it has only 23,000 miles. I did check the plugs, cap, rotor, and wires and all are fine. I started it up last Saturday and it seemed to run okay, but on Sunday it immediately ran rough when started. I understand that the EGR system is an issue with Accords but this one has such low mileage that it would seem unlikely to be the cause of the problem.
Is the check eng light on? If so get it scanned and let us know the code. If the wires are original they are 13 years old and need to be replaced.