This seems to be a TOP secret subject. I cant find any info on where to

a) Locate the MAP sensor
b) Remove it

and

c) Clean it.

I have spent hours trawling the net without any joy, can anyone please please help.

DaveT ST to the rescue - where ar though ?

It's behind the throttle body on the inlet manifold.

Thanks. Can you perhaps post a pic of exact where. I had a quick look, and couldn't spot it.

What should I use to clean it? Will carb cleaner be ok?

Do I need to remove the TB 1st to get to it. It would help if I just new what to look for, bit I'm a bit clueless on this one.

I can't post a pic sorry, I don't have an ST anymore.

You'll see an electrical connector just behind the throttle body on the manifold, quite small, that's it.

You may find it's the throttle body that needs cleaning though, they can gunk up and cause running/idle issues

Thanks, I cleaned the the TB, and yes they do gunk up. You should see them with the fuel in SA.

I found this: See attachment.

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR. The MAP sensor is mounted on or connected to the intake manifold to monitor intake vacuum. It changes voltage or frequency as manifold pressure changes. The computer uses this information to measure engine load so ignition timing can be advanced and retarded as needed. It performs essentially the same job as the vacuum advance diaphragm on an old fashioned mechanical distributor.

On engines with a "speed density" type of fuel injection, the MAP sensor also helps the PCM estimate airflow. Problems here may cause an intermittent check engine light (light comes on when accelerating or when the engine is under load), hesitation when accelerating, elevated emissions and poor engine performance. The engine will run with a bad MAP sensor, but it will run poorly. Some PCMs can substitute "estimated data" for a missing or out of range MAP signal, but engine performance will be drastically reduced.

MAP Sensor Strategies: Some MAP sensor problems are not the fault of the sensor itself. If the vacuum hose that connects the MAP sensor to the intake manifold is loose, leaking or plugged, the sensor cannot produce an accurate signal. Also, if there is a problem within the engine itself that causes intake vacuum to be lower than normal (such as a vacuum leak, EGR valve that is stuck open or leaky PCV hose), the MAP sensor's readings may be lower than normal.