Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Here's one for you all.

Morning all,
From time to time, not at all a frequent occurrence, I have noticed that as I slow down to enter my barn and slip into neutral, the revs will rise to a couple of thousand rpm and then fall back to 900rpm. Also, depending on the weather it seems, it can take a while for the revs to stop rising between gear changes but if I bring the car to a halt the revs will drop back to normal. This is quite different I THINK from rev hang which the 2010 Roadster does not seem to suffer from - or am I wrong ? Anyway it's being doing this for years so I don't think that it's particular problem but I would like o know what you all think.

Faulty IAC valve maybe

In 2010 they changed from series 2 to series 3 Roadsters. So both could be possible re your Roadster. I had a series 2 from 2008 with a high amount of rev hanging which was cured by getting another ECU from MMC. Hp was around 205 Hp or so but the engine was very smooth running with a good „felt“ torque. My 2010 was the earliest series 3 in the summer of 2010 with the wider front axle and around 230 Hp in form of the then new Roadster sport. This car never had an issue with rev hang. But as Richard says the fault of your engine could have another cause.

My 2011 Roadster Sport did that and I cured it with a new IAC. Bought via Amazon from the US. Can’t remember how much it was but I have the Motorcraft part number if that would help.

Don't discount something mechanical. Maybe an occasionally sticking throttle cable, or dirty throttle body butterfly. It only takes a slightly open butterfly to affect the idle. When doing some work that required me to remove the throttle linkage setup, and when I re installed everything, the bracket that holds the cable was every so slightly not in the previous position, although it's bolted on. This had the effect of the cable slightly opening the butterfly, and therefore increasing the revs a few hundred rpms. Also if the butterfly and or mechanism is all dirty, this might prevent it from closing fully on occasion. So just something to be aware of and tick off the list.

Okay thank you for your replies. It does have the wider front track by the way. I do pay attention to oiling things like throttle cables etc but yes the doc valve could have something to do with it or maybe something else very simple. I'll keep an eye on it. Thanks.

From an earlier thread, ICV from Ford Escape 3.0 V6 to fit 2009 Roadster (assume 2010 the same) is Motorcraft CX1899. This was ordered via Amazon with one week delivery - click image. Apparently they are £200+ from dealer! It was found to have the exact markings of OE one, 3F1E-9F715-AC FK13.



Hope this helps if new one needed. BTW it cured near identical symptoms to yours.

Thank you Richard.I'll get one.

I have one. PM me

That’s the one. Cost me £50 from Amazon UK and arrived in a week. I had previously bought a supposedly identical one from a UK parts dealer and it turned out to be a cheap Chinese copy. Sorted low rev hang but introduced a hang during gear change when accelerating hard - bit scary the first time but proved the IAC was at fault. I think you will find the IAC on the 2010+ Roadster engines are different to the Mk2 and Mk1.