So I got the "new" motor into my "new" 85 truck, and it runs good, except for one thing. It has a very audible miss/lope at idle and will sometimes bog enough to kill the motor... I can baby the throttle some and keep it running, but if I let it sit there it will eventually die.

I've gotten as far as checking the timing (of course, I inspected other stuff... cap, plugs, rotor, throttle body, vacuum hoses, etc), but I'm stuck there for one reason: The wiring harness that runs from the injectors and all other stuff on the passenger side of the motor does not have the service check connector on it that is referenced in both manuals I have. The OLD motor does, but this '87 one doesn't. Man I do NOT want to swap the wiring harness over either... :| Anyone know what's up with this? How do I check codes or set the timing without that connector? Is there a different method that the chiltons/haynes manuals are not telling me?

The new motor is out of an '87 4runner, and the truck is an '85 SR5. The old motor had a gnarly exhaust leak and a temperature control problem, so I yanked it in favor of one in better condition. I also installed a Downey header at the same time, and it's currently running open header until I finish the exhaust. I've HEARD that on the Downey headers, the O2 sensor placement is not ideal since it doesn't read off of all cylinders, could this be an issue with the sensor not heating up enough? The reason I ask this is because it runs and idles GREAT in open loop mode when I first start it cold, but as soon as it warms up a bit it starts running like crap.

I road tested it and the motor runs great and has ample power (for a 22re), but it just won't idle right.

How much back pressure do I need, obviously some is needed but should it affect the motor enough to cause it to stumble/lope/misfire at idle? Just throwing it out there.

Any of you Toyota gurus got any ideas? Anyone done a conversion to a heated O2? I assume I would just need a proper O2 and then wire it up to ignition and ground as well as the O2 wire... would it be worth doing with this header?