I installed a denso 4-wire o2 a few weeks ago. 95% of my hesitation problems went away, but it still drinks too much gas.

When I hooked the wires up, I didn' cut the signal wire and it's about 1.5 to 2 inches longer than stock I think. The connector was crimped on nice and tight with a bit of solder.

Would that extra bit of wire length be enough to effect it?

Also, does the o2 need to be specific for the computer, (as a few people have told me) or does any universal heated o2 work? (as I remember reading here)

I sorta suspect a vac leak somewhere too, as that's what my symptoms suggest, but I doubt I'll find one when I check the system this weekend.

 

As long as the connection is good, a few inches in wire length won't matter.

I have used 3-wire heated O2s before replacing the factory unheated O2. I think the X-reference I used was for a 93 Corvette. You need a signal wire and 2 more wires for the O2 heater. Not sure why you would need a 4-wire sensor, but I'm not an O2 sensor expert.