Rover 400 Problems.........

Check for a cracked or leaking or disconnected vacuum air pipe, there is one that goes to the ecu on 214s that regularly falls off or snaps off at the ecu and gives this symptom.

mrcheerful

Hi, I've got exactly the same car, I started getting those symptoms too, turned out to be a hole near the exhaust manifold. This is from memory, but as I understand it, (from what the mechanic told me), the hole in the exhaust screwed up the lambda sensor (exhaust oxygen sensor) reading so the ECU tried to over-compensate which caused occasional misfire and a higher idling speed. It was also sometimes difficult to start, and had noticeably lower power.

So... see if the exhaust is blowing anywhere (especially under the bonnet).. and if not ask your mechanic friend to check the lambda sensor. May be worth a go anyway. You could also ask a garage to check the diagnostics port of your MEMS ECU. That'd tell you if there's a fault with something. The MEMS is obviously idling high for a reason, and that should hopefully tell you what it is.

Mine also idles high because of the wonderful K-series engine design flaw which lets the throttle stick open at high RPMs. very safe!!! But you've had your throttle body assy replaced so it's probably fixed on yours.

It turned out to be a faulty ECU............all sorted now