1.8 cold running - jerking, or hunts/stalls
 

I have a 2000 W reg Rover 75 1.8 manual (non turbo) with a strange issue when started from cold (as in a cold engine..... the weather is irrelevant) and it’s fine as soon as the temperature gauge moves.
If I start up, drive down the road and lift off the throttle in say second gear, the car will jerk/kangaroo. To avoid this jerking I dip the clutch before lifting off the throttle. What happens then when I dip the clutch is the engine hunts and often stalls unless you rev it a bit.

If stationary and I blip the throttle, as the the engine revs rose, it sort of skips/jumps at approx 1800-2000rpm.

I had this exact issue on a 2000 W reg Rover 45 1.8 10 years ago, and in 6 years I NEVER got to the bottom of it!

I have changed the 02 sensor. No difference.

Not inlet manifold gasket is it? Check plugs for coolant. Also try resetting the IACV, ignition on, don't start the engine, press accelerator pedal 5 times quickly, ignition off. Restart the car. All I've got for now:}

A fine crack/tear in the vacuum hoses - :shrug:

That sort of thing used to happen if the choke wasn't working and the mixture was too lean. How it works on the petrol engines though I don't know as I run a diesel.
---:shrug:

engine coolant temp sensor ? cant you run the ipk temp diagnostic to check ?

New inlet manifold gasket fitted last year when head gasket was changed.
Plugs look good.
Temp reading fine.

I’ve ordered a second hand throttle body and new idle air control valve. I don’t think it will make any difference as I changed these on my 45 and nothing changed.

Make sure that the throttle cable is properly adjusted with a little slack to allow the arm to rest on the throttle stop at idle. My Rover 25 came to me with similar problems, I found that the throttle cable in previous ownership had been overtightened to get the revs up to try to mitigate a stalling problem from cold. I adjusted the throttle cable correctly and it solved everything bar the stalling problem which was more evident without the bodge of the overtightening. It took a T4 session to get the car running better and I think the base idle index is still in need of some attention but I hardly use the car and it runs in the main well enough for my needs for now. I hope to get it fully sorted in time but other things to sort keep getting in the way. :getmecoat: