SLROC Forum

Hi All,

I have a 1993 4.2 petrol V8 Rangerover, starts and runs great, its only covered 90k miles and has Full Service History with the last service only a couple of thousand miles ago.  It has started on occassions to rev up and down when ticking over which can sometimes cause it to cut out, its an Auto so a nuisance when it does this. Doesnt do it all the time and usually after being driven for about an hour. I know this is a problem with many models of cars but wondered if someone could guide to what things I should check......

Ta

Donald.

hi there,
1st check from the plugs back,otherwise try this,,,,,,,

i,m not sure if this will help,but have a look thrue the workshop manual for something like a P.T.U.,,,,why do i suggest this,
well my 300zx cut out when it was warm,otherwise runs fast and true,,until it warmed up a little,it was my ptu(power transistor unit),cuts the engine out,,,,now on the 300zx it has seperate coil packs,this is what a ptu does,send the correct pulse and amount of currant/voltage to each coil at a presice time of fire,vroom,,,
i hope this has helped or maybe it's made it worse.
good luck

The base idle could be at fault. I am not clued up enough on the EFI's to know what to do but I can put you in touch with a man who can talk you through it

Hi Steve ,

That would be great thanks, would like to have a go at
fixing before taking to the garage but no idea where to
start.

Air bypass stepper motor?  Left hand side of the plenum (the silver bit on the top with 4.2 written on it!) there should be a 4/5 pin connector block.  Try disconnecting that and see if it's any better/worse.

Has your fuel consumption gone up?  If so it could also be a faulty Air Flow meter.

it was my ptu(power transistor unit),cuts the engine out,,,,

The 4.2 has a distributor not coil packs.

Have you checked all the hoses etc to make sure you dont have an induction leak??

PM sent

Hi ive seen a v8 with a partial melted coil... It ran fine but cut out at tick over (time varied) The voltage had dropped. Check all leads for blue spark to earth. How clean is your air filter?? These are simple things to check Good luck

Thanks Guys ,

I will try some of the suggestions, it's intermittent so don't
think it will be air leak from hose

DN