Lol its something that's used in older cars for cold starting. A small unit filled with wax and has a pin coming out of one end fitted on carbs (unsure if there on throttle bodies but worth a thought) basically it's connected to the throttle and when the coolant gets warmer the wax expands and pushes the throttle open slightly to act as kind of an an automatic choke. If that makes any sense lol. If it's not got one then there will be a idle control valve of some sort.

Ah right yeah I get what you mean, never even heard of one before haha! It's got an idle control valve and I've got a spare that I'll swap across to test

I tried my spare ISV and it didn't make any difference.

Is there a way to check that the ECU has cleared properly after changing the blue temp sensor and doing the 3 revs above 3k trick?

Try disconnecting the battery and touch the terminals together that'll drain any residual voltage in the system. Maybe leave disconnected over night. Though a couple minutes should do it. Itll reset any values in the control units. Never heard of the coolant temp thing but worth a go.

I've done that a few times and nothing happened. Apparently the touching terminal wire trick doesn't work with these older ECUs anyway haha

Ill give you £200 for the car and be done with it

Hhaha thanks for the offer mate but not a chance, I've got more than £200 worth of suspension on it! It'll turn out to be something small and stupid I know it but my plan is to have the car up for sale later this year. I've had it for about 2 years already but I did the GT conversion over summer 2015 and that's when these problems started

I did the same thing to my aav. Problem i had was a school boy error of putting the wires for the starter on each thread rather than together so had a drain.

This was initailly hidden by other issues as the conversion came from an untested car so i had to chase it around the bay eliminating things

If you do come to sell it later on in the year give me a shout. I may be interested depending on how I am financially and with my other projects at the time.

I've got the drain issue sorted, it was just a knackered battery so it's just the cold start misfire problem to fix now and then she should be golden. I think I really just need to spend some proper full days on it rather than an hour here and there when I just poke stuff and see what happens.

OK kwijibo, will do. The plan is to sell it around July time when the insurance will be reaching it's end. By then I'll be long done with my studies for the year so I'll actually have some free time and energy to get it fully sorted

Right, I've actually had a few free minutes to spend poking around. Disconnecting the blue temp sensor makes the revs drop and make it worse. Adjusting the dizzy seems to only increase/decrease the revs.

Also noticed that it sounds like there's an exhaust blow when cold. Is it possible that there's a shitty gasket somewhere that seals off when the exhaust is hot but causes bad lambda readings when it's cold?

I've changed the exhaust manifold gasket today and it did seem to make it a little better, not perfect but better. There is a slight blow from the downpipe gasket as well but I didn't get a chance to change that. There was also some oil/crap in the distributor cap so I cleaned that out. I'm hoping that the multiplication of exhaust blows is causing the issue and sorting the others will fix everything!

I've also just seen that the flap in the air box only works when it's hot. I don't have the hot air feed from the exhaust manifold so I'm guessing (if this is true) then it could be a contributing problem

Just so everyone knows, I have started another thread as I think the problem has been a bit lost in this 10 page epic. The new thread is just called Mk2F GT cold start misfire as this is the remaining problem with the ol' girl. Thank you everyone who helped in this thread. hopefully the new thread will draw in some more people who might be able to solve this 24 year old German mystery.