When I start the car from cold it gets up to around half way point on the temp gauge but then drops off back to below the white line and while its in this position the car runs slightly worse but noticebly worse... around 2mins after driving it shoots back up to normal again and the car runs great again for the remainder of any journey. Any ideas what could be going wrong here?

magic!!!

 

strange the temp gauge shouldn't have anything to do with the way the car runs...

that is the ecu temp sender unit.... so if both are going funny, i'd say maybe a coolant issue, air lock, water pump, thermostat....

 

but I could be wrong... it might be magic... LOL...

Mine had a similar problem with regards to the gauge being erratic,

turned out to be the spade connector on the sensor itself had become loose.

I soldered the rivet type fixing and it has been OK since.

I did not have the rough running though so may not be the same issue but may be worth a look?

read my post... :)

Could no believe it,:ohmy: you just pipped me to posting. I only noticed your reply as I posted.

must type quicker.

Good point though. :)

lol... :)

Which sensor are we talking about, temp sender? Where abouts is this located?

there are two temp sender units on the front top coolant pipe.

 

the one with two spades is the ecu temp unit and will control how the car runs.

the other one with the one spade is the temp gauge unit.

 

check them both for corrosion and damage... they could both be playing up but it could also be a coolant issue. :)

 

good luck..