Thread: 3.9 i cutttiing out

Sorry - see below!!!

Hi Zana,

It's not an easy one as it's obviously intermittent. However, I'd have a look at the both fuel pump and main ecu relays: - they're located under the drivers seat behind the ecu. I(f they're original, they'll be aluminium cased Lucas - aftermarket, brown Bosch).
I had the same issue and replaced both which fixed it - didn't have the time to mess around with it at the time but later investigation revealed a sticking FP relay.
Just note though - they look the same and do the same as a standard 5 pin relay but have a diode in them which protects the ecu from back emf . They cost about $30 more than standard relays..pays your cash etc!

The revs flaring to 2k when you restart - Do you get an irregular idle normally? If so clean the Idle control valve located at the back drivers side of the plenum - idle problems

Other than that it could be a few other things - but check those first as they're cheap.

Sometimes cutting out on light throttle is caused by a worn out Throttle Position Sensor (TPS) which develops a gap in the resistor just off idle.

Usually the stopping is preceded by a "tip in" hesitation, like when you go down a hill with foot off the accelerator, then resume speed by placing your foot back on the accelerator.

There are posts on here on how to check the TPS.
Regards Philip A

Thanks very much for your help Hobbes and PhilipA.
l was starting to think about the fuel pump so l might turn keys off next time it is playing up and check fuel preasure (at filter l suppose would be easyiest and safest). The engine normally idles very smooth and at a constant RPM so it might not be the TPS. Heres hoping next time it plays up l can find something. Thanks again. Zana.

It will idle OK with a dead TPS, and maybe rev except maybe with a cough. It is off idle where it usually sits when you are doing 60-80 or so or whatever you do most.
Regards Philip A

Thanks again PhilipA. Yes it could be the TPS . l will check the posts on it to see if i can work out how to diagnose the TPS .
Regards Zana

Hi, l replaced the coil and all seems well. l think because the coil was playing up it was confusing the computer hence the high and flucturating idle (idling at 2000 rpm at times and at other times a surging idle from 700rpm to 2500 rpm but only when the coil had caused the car too miss or stall intermittely) Just goes to show that we can all get caught up with all the computer controlled stuff and think it is all too hard, but if we go back to the basics most of the time we can work it out. THANKS FOR ALL YOUR HELP. RegardsZana. ( happily driving his range rover classic again)

Hi, l thought the coil had fixed the problem but no luck. Have since replaced fuel pump still the same problem. Then bipassed the inertia switch ( the switch under the passenger seat that cuts power to the fuel pump in a roll over sittuation) still no joy. It has spark when it does not start, so l am still leaning to fuel supply. When it stalls there is a heavy fuel smell and when i wind it over there is smoke still coming from the exhaust so maybe an over supply of fuel. Any ideas would be great.
THANKS ZANA