Occasionally Stalling

[PeterDavisX300]

1995 3.2 X300 115k miles. A rare Happening I must say. What happens is, about one in twenty stops, the car goes 'low' at idle, say if I happen to have to stop quickly, or if I have full-lock-steering whilst creeping and parking. The car is a little slow on the idle whilst warming-up in the morning, say for the first 5-6 miles, but just very recently has done this 'stall' whilst well warmed up. So, it does the low idle down to about 600rpm, but mostly picks-up almost instantly to 750rpm, but on the odd occasion doesn't do the 'pick-up' to 750, then stalls. I'm sure I've seen something on the site about this, but can't find it, and seem to remember it was to do with a V8. Fuel consumption remains as it normally is, the car runs really well to the red-line in all gears! It's smooth, and gear-changes good. I service it regularly and check things constantly. (I'm a mechanical engineer) I've got the right Plugs in, and I 'chopped' them just the other day, they are tight in place, the coils are all OK and not split so are the low-tension wires, the injectors should be OK but I haven't checked the spray cone for a while, but they had new seals about 10k ago. I cleaned the MAF about 3k ago, and all wires to all sensors are clean/good/tight-in-place. I've got an aluminium crank-advance pointing to the pulley, and I've just cleaned the sensor, the sensor is a JLR item about 5k of use. All the jubilee clips are tight for the inlet side, and the EGR is nice and cleaned up about 3k ago. The engine compartment is Very-Clean though I say-so myself, so dirt or filth isn't a problem. The only problem I had recently, was when the coolant rail below the inlet-manifold blew it's bum off, and sprayed coolant everywhere, that was about 2k ago! The engine didn't sustain any damage I reckon because I stopped quick and clicked the 'full-power-fans' in (I have a separate switch to manually control the electric rad'-fans, because I have taken the car to Malta a couple of times) The car runs really sweet apart from this new development.

It doesn't really bother me much, except the car is due a couple of longer than normal journeys during Easter, and a trip to France/Southern Italy/and Africa later in the year (ho ho) So, any thoughts would be very welcome. Peter.

[steve_m]

I have heard that the throttle butterfly can get gunked up and stick; might be worth a look?

[Popsjag]

It might be worthwhile having a look at the TPS (black connector below the butterfly). These have been known to play up. It might be reading a false position.

[PeterDavisX300]

Thanks to both. I've cleaned the intake with thinners, and I'm waiting to see if that makes a difference. I'll check the connector below asap. I'll let you's know.

[davidr]

Is the idler stepper motor a bit sticky?

[PeterDavisX300]

Just as a wee 'feedback'. I did as Steve M suggested, and had a clean-up of the throttle butterfly, this helped a good bit and it hasn't stalled yet after about 300 miles. It's still sometimes a bit slow, and I still have to check the wee idler stepper motor. But I'm getting 26 ish to the gallon so all can't be too bad!