Rangie Mis-behaving

Can anyone please help - Im running out of ideas
My `86 3.5 EFI starts first time on the key and wil run for Between 1 and 10 minutes and then die as if switching it off.
This happens wether being driven or on tickover and will then not start - will just turn over and over and not attempt to fire
If left for half an hour or so it will fire straight up and repeat the process
Upon breaking down the first time the RAC couldnt fix it so after I got it home I changed the coil,distributer cap,plug and h/t leads and rotor arm - no improvement
HELP

Hi,
I am not an expert but I wonder if it could be the ECU or associated components. From what you say it sounds as though the engine starts to warm up and then closes down because the ECU is discovering a fault with one of the sensors or controlers.

The fact it will not start while semi warm would seem to suport this.

Check the air filter and associated airways. There is an air flow device in the air feed and as far as I know the vane on that needs to move freely.

I am sure others will be able to help you more.

Hi Big Al,
I would agree with mikeljones that it sounds like an ECU problem.
The ECU is normaly the cause of behaviour problems with running and ticking over of the 3.5. Providing you have checked the basics first, then you should try to borrow an ECU and swop it over to see if it cures the problem. Its located under your drivers seat and just unplugs.
I have an ECU for an 86 you could try, but live in Essex if that helps you.

Rangie427 http://myweb.tiscali.co.uk/rangie427/index.htm

Im getting more confused - Yesterday I sprayed every connector I could find under the bonnet and then started her up - left on tickover for 15 minutes and then drove about 35 miles with no problem - YES RESULT!!
NO!! - came to her this morning - started her - Problem returned!!
Tried her again this afternoon and she`s running again
Other thing Ive noticed - weather its connected or not is that when started cold she kicks out an enormous amount of white/light grey smoke which continues until the temp gauge starts to rise and then she runs clean again

Finally have cured the problem... Tried another ECU on it - no good - called in the pros - auto electrician came to it - messed about, then informed that I need a range rover specialist - charged me then left.
A few phone calls later - enter the specialist - diagnosed faulty coil and throttle potentiometer - charged me then left.
Ordered said items and fitted them - no good!!!!
Now spent in region of £460 and still a pedestrian.
A mate of mine came round(who by the way hates range rovers) and changed the over-fuel cut off relay - cost £3.25 - and the bloody thing fired up. Will now put out contract on the two cowboys who mugged me!

Hi Big Al, glad to hear it is fixed but sad to hear you were muged on the way. What happened to the good old days when the mot was "No fix no fee". When I started out in electronics my old govenor used to make me stick with a fault until it was found and then replace the part responsible not the rest of the bloody vehicle.