Le Mans misfire on anything more than 20% throttle...

I have a very odd misfiring problem with my Le Mans.

1) Starts OK, tickover OK.
2) Revs OK if you open the throttle REALLY slowly.
3) Once it warms up the tickover falters and eventually it stalls!
4) Try to accelerate normally using a moderate throttle opening it stalls!

What on earth do I look for? I really need to fix this in situ as its virtually undrivable at the moment. Checked HT leads in the dark - no arcing.

Fueling, or ecu related..

Both the lambda sensor and coolant temperature sensor reduce the fueling when the car warms up, if the fuel pressure is too low to begin with, then this will just cause the car to stall when the throttle is slightly opened.

First of all, warm the engine up to running temp, and disconnect the connector from the lambda sensor (bolted into the downpipe after the turbo - sensor going through heatsheilds). See if the problem persists...

Reconnect, and then disconnect the coolant temp sensor connector (on lefthand side of thermostat housing), and again see of the problem persists...

If the problem goes away completely, then it is related to those sensors, if it just improves slightly (i.e not stalling), then you have problems elsewhere, such as fuel pump pressure, or voltage etc...

It could also be a faulty map sensor, though it is very unlikely.

Its a shame my diagnostic reader does not work on Lemans models for some reason, then you could check the true readings of both sensors.

Fueling of some sort,could be the regulators or filters .

I wonder if it it the throttle pot, it has 3 positions, idle, on and Full (>70% throttle). Perhaps it is stuck at idle and you engine is not getting enough fuel on throttle to run.

Anyway, Dr G will be along soon......

Seems to be the season for missfires! Might be worth checking this thread too:

http://www.renaultalpineownersclub.com/ ... .php?t=975

Good luck!

[Alpineandy]

Answer number 1 should have been 'check your earths' followed by Mr G!

It turned out to be the distributor cap - shot to hell. Thanks for all the suggestions. I've also replaced the HT leads with Magnecor and replaced all the spark plugs and she's goes like the wind now. Also a misfire near the redline which I'd taken to be a soft limiter has gone away.

HOWEVER, the car now stalls nearly every time I stop. Thought it was me screwing up clutch control as the car's been worked on for a while and I'm out of practice. But when I tried pushing the clutch right down while moving at 30 mph in third and the revs dropped straight past the 1000 RPM idle without even a hesitation and it stalls. You can restart by popping the clutch and do that over and over again. Idles fine as long as you don't accelerate again. What do you guys reckon - idle control solenoid, MAP sensor or ECU?

Start by cleaning up the ide control motor, yes, as that's the most obvious. It might be unable to open fully

also check you are getting power to the ISCV.