Car: 1998 Civic LX, automatic, 180k miles

work done: timing belt at 124k. past couple weeks: new distributor cap, button, ignition coil, ignition control module, fuel filter, sea foam treatment in gas tank and injectors.

Spark plug wires are all functional; haven't checked the plugs yet (but I will replace them if/when I get to that step - they were replaced with the timing belt at 124k). All fluid levels are fine. Can't find any air leaks in hoses. Also: my gas mileage has not been noticeably affected by this (just a random thing I noticed: I always check my mileage when I fill up).
-none of my 'maintenance' has fixed or alleviated the issue.



Ok guys, i've been sifting through previous threads to find help with my problem and am still stumped (and now quite frustrated). Hopefully I can get some help here.

The problem: the car 'stutters' or misfires under acceleration (always worse when the car reaches operating temp). It is not constant: sometimes it will stutter during acceleration then come out of it and accelerate to 4 or 5000 RPM perfectly. However, once the car is at operating temperature the car will 'stutter' 100% of the time if I try and accelerate hard from a stop.

If I'm in 3rd or 4th and push the accelerator down too far (1/2 wayish) the car will bog down, *however, I can manually downshift and when it revs to the higher RPM it always feels smooth. If I put the car in neutral and rev the engine it exhibits the same problems.



The car idles fine but it bogs down if it's at operating temperature and the A/C is on - however this is not constant either (though it's about 80% consistent).


CEL codes: The car has been like this for about 2 weeks and only just today threw these CEL codes.
P0301 - Cylinder 1 misfire
P0302 - Cylinder 2 Misfire
P0300 - Random Multiple Cylinder Misfire
P1399 - Manufacturer Control Ignition System Misfire
- I'm guessing the last one is for the Ignition Control Module: is that correct?


What can it be? And why isn't it a continuous issue? If it's the spark plugs, why doesn't it happen during any heavy acceleration? What else should I consider? I'm trying to work my way from the inexpensive solutions to the most expensive to save on what little money I have. Please help! Thanks in advance for any assistance you can give. I'm by no means a car guy, but I know enough to get my hands dirty and attempt some fixes (i've done everything so far - except the timing belt).