With the broken IACV, i'm wondering if the whole unit is been busted by slapping against the firewall. I had read somewhere that if its not working properly, it can cause misfiring issues.
As i said, i have a new one on the way. And I'll be adjusting my other engine steady to push the engine further from the firewall to give it some clearance.
I'll probably order one of those T300. Being pre OBDII compliant is a bit of a pain! It may be able to tell me if the stepper is busted too?
1 month for shipping, so will be a while until i can report back 
I'd already stripped of the wiring tape and repaired some of the wires there years ago (sheared a couple when rubbing on the air filter clips), and checked again just recently. Seems ok now. Although there are a few wires that run down behind the IACV and looks like they go to a sensor plug, so i may try and check that too. That may have been squashed and maybe whatever sensor that is could have hit the firewall too.
One thing i've not managed to look at is if the throttle body is cracked or the manifold. When that engine steady bolt sheared, the engine was crashing against the firewall. I initially didnt realise that was the issue and carried on driving home for a few miles. It was about 9 months ago when i fitted the left hand engine steady.
