Hey Everybody, thanks so much for your responses.
I live in Santa Cruz and bought from a private party in San Jose. The test drive seemed fine and I even had a friend's mechanic take a look before I paid - he thought it was fine but clearly he wasn't very thorough! So I bought it (paid cash), and headed back home. It was running smooth and strong over the SC mountains. I didn't push it - was just enjoying the drive. As I neared Scotts Valley, I was traveling downslope at about 65-70. I pushed on the accelerator lightly and the car seemed to hesitate a bit, i let off and then pressed again. the car responded by hesitating even worse almost slowing. Then the engine died. i drifted for a short ways then restarted the motor. At this point I can tell you that the front three cylinders were dead, but what happened was the engine started running very roughly and a little smoke came from under the hood and it died again. after that I just pulled it over. One attempted restart later I called for a tow.
When we got it back to the shop my mechanic hooked it up to the computer, which gave the code that the cat was bad, when it was taken off later the guts of the cat were hanging out from the bottom; also the code for the V-Tech solenoid indicated a problem there. When he did the compression check, all three front cylinders had very bad compression 40psi or so (back ones were fine). He noted that the heads had been changed very recently (by an amateur, apparently, because the rocker arms were over-tightened with no gap). Apparently, most of the compression was going into the crankcase somehow. So with my permission he yanked the front head on the assumption that a bad head job had been done (here's where the labor charges started adding up). Once there, he could see fairly deep scoring on the cylinder walls in the front three cylinders. I halted work at that point. no clear determination was made of the cause. the heads were clearly brand new and the gasket was nearly perfect, the pistons were clean and undamaged. The scoring seemed to be of concern to the mechanics, I am no judge, but they were not horrible.
A gearhead buddy of mine came by to look at it. and told me that he had had a Honda engine on his wife's car create similar problems due to a bad front cat. one of his suggestions is to get a new cat and put it back together and see if it runs. If I go this route it will cost a new cat plus about $600 in labor. He was clear that it may not work.
I have been looking for an engine or a short block. they seem to be in short supply, either that or I do not know where to look. additionally the refurbished engines I have found are all more than $5000 and that is without the $1000 cat! i did locate a couple of used engines on the east coast, it seems silly to me to ship one all the way across the continent. i would like to find something more local to San Jose CA. If anyone has a suggestion on where to go I'd appreciate it.
Also, can someone help me with the proper engine #? I think what I'm looking for is a J35A6. Is that correct or is there something more specific?
Thanks for any additional input you want to share!