Misfire Issue Options

[PaukST]

So, about 3 weeks ago my 94 ST started getting a misfire. Initially, it was only under mid-heavy load, like going up a hill at relatively low revs. I replaced the spark plugs and it got better for a few days, then went back to the occasional misfire. However, a few days ago it suddenly got way worse. I pulled up to a stoplight, but when I went to take off, it would barely go. It's nearly undrivable. It's pretty much a constant misfire now. It seems to be cylinder #2. It tries to die if i pull a spark plug wire/unplug an injector from 1, 3, or 4, but nothing changes when i unplug either from cylinder #2.

I had changed out my spark plugs and wires probably less than a year ago. I rebuilt this engine June of last year, and have had a VERY slight miss with this engine all along. I assumed it was due to the ever-worsening crack in my exhaust manifold (located closest to the cylinder #2 exhaust port).
So:
---Rebuilt 18 months ago
---Replaced spark plugs about 2 weeks ago, the old ones weren't broken or particularly noteworthy
---Replaced spark plug wires within past year
---Switched over the injectors from my other 7A-FE thinking one may have been clogged, no change

Anyone have any ideas? Advance tells me they can't check the CEL code on anything pre-96.

Second edit to add that I replaced my distributor cap/rotor around the same time as my spark plug wires. I took the dist cap off today and cleaned up the contacts, they looked fairly bad again. Unfortunately that changed nothing.

This post has been edited by PaukST: Dec 12, 2013 - 6:15 PM

[Smaay]

could be the distributor cap, could be a valve out of spec.