The V8 Owners Forum -

Stephen,
Take the IAC or stepper out of the equation. Remove the pipe connected to it, block the pipe and the stub on the stepper. If idle is too low you can increase it by adjusting the base idle screw near the throttle spindle. The idle should be around 750 rpm.
See what happens then.

The tempearture sensor measuring 9k was telling the ECU that its temperature was -10 deg C, was it that cold??????

If fuel pressure is 36 at idle then it is too high,check the vacuum pipe from the plenum for cracks or leaks. The plenum vacuum modulates the fuel pressure regulator down to about 30 while idling.

Forget the LPG until the engine runs fine on petrol.

Are your dizzy cap and rotor arm genuine Lucas or pattern rubbish?

jw

Stephen,

Before I reclaimed mine from the garage they reckoned it was the Air Flow Meter (at a shade under £400 for a new one).
They were convinced it was the Air flow meter and said they change it (an easy job) and if it didn't fix it they swap it back and I'd only pay the labour. Well, they were wrong.
Whilst I had the new one in and trying to road test it, I took the old one apart. The input and output barrels come off (carefully and you might be able to re-use the gaskets) and you can then get to the 2 resistors or hot wires in the main body. They are very delicate, but can withstand a squirt of carb cleaner. It's unlikely, but you might have got some gunk spat back from the engine or from the crankcase breather that might have got on the wires. Whilst you're at it you can give the barrels a clean too.
Just a thought, it's what I did to mine.
Yes, I know mines not running right either, but it's certainly no worse than before - if you can start it, that is.

stephenmcdermott wrote: Fuel pressure is 36psi all the time

How're you measuring it? You should see 36 psi ish minus manifold depression with engine running and the vac all connected up, if you're really seeing constant 36 psi then double check the vac line from the plenum to the fuel pressure regulator.