Sorry if there is a thread on this topic already, I looked but didn't see one for the same thing.

Ok, so I have a 1993 sc400. The ran ran beautiful for the 2+ years I owned it, about 5months ago if I let it sit for more than a day(say if I had a day off) the next time I would get in it, it would have a slight missfire then about a mile or so of driving it would return to normal. If I drove it daily I had no issues at all. Well I bought a truck for work and it sat for about a week, now when I go to start it, it for a fact is not running on all 8 cylinders. It sounds like a Subaru to be honest. I've replaced plugs and wires, and it had no effect at all. I have no CEL so I can't get an idea from jumping the diagnostic port. I am personally unfamiliar with OBD1 systems so I'm pretty in the dark on this one.

 

Check the coilpacks, and collapsed cat.