All 4 cylinders misfiring
 

I have a 98 civic LX, just had the timing belt changed last year, for the last month has started misfiring. I put the scanner on, got these codes: P0301, 0302, 0303, 0304 and 0300. All four cylinders misfiring with a random misfire to boot, lol.

I'm wondering if it slipped time, as in the timing belt slipped a cog? Or if it is a vacuum leak somewhere, probably into the intake manifold, that is causing this? I changed the plugs and wires and distributor cap, but it wasnt the issue. Any thoughts on what it might be, and what to check next?

did you replace the rotor with the Dist. cap? (if not, it would be a good idea)

I think that it would be best to double-check that the timing is set right (just to verify that the timing belt didn't jump a cog)

Yes, replaced the rotor when i did the cap. Am wondering if it might not be a vacuum leak?

if its gettin spark and fuel, it has to be the timing... if it was a vacuum leak, your car would just idle all retarded

Also check the coil and ICM inside the distributor.

How does the rotor look?