740 & 760 740 won't go much above idle. Code 223 IAC (solved)
Yet another 740 issue. Love these cars but I need to get better at fault finding.
Basically the car starts immediately and has a high idle, around 1200. Try and touch the accelerator and as per the attached video she just starts surging to a few hundred RPM up and down (obviously not driveable, unless your happy with 5KPH and downhill). It's like as if the there's extra air going through the throttle body but no extra fuel.
- Replaced AMM, no change. Tried disconnected, slightly lower idle but same issue.
- Searched for vac leaks, nothing obvious.
- Disconnected TPS and IAC plugs to look for changes, nothing. Isolated the IAC VAC hose temporarily and goes back to a smooth 700 RPM idle, won't go above other than same surge.
- Fuel Pressure Regulator has no leaks at diaphragm
Car history was laid up by previous owner for several months outdoors and was apparently running fine before being parked (other than brakes keep locking up after car warms, but no calipers seized and no issues cold, most unusual).
So I'm thinking obviously 223 could cause the high idle and the IAC will be swapped out / cleaned when I get the chance..... But can 223 cause the issues I have?