96 power dropoff

[alsdatto]

i have just joined today due to reading the thread that widepud was writing and i think i have a similar problem and would appreciate any help.
my disco is a 96 v8 with 205000km on the clock
I seem to completely loose power whilst driving and it seems to be at around 1800rpm.
initially my mate, a mechanic, thought it could be a clutch related problem, due to the expense i said how can we get around to a clutch, so we relaced the clutch ***** and then the master cylinder. Problem still there. we then replaced to feul filter, feul pump, air flow meter and just last week the clutch was replaced. so fair to say im fed up with throwing parts at it to diagnose a problem that is not reading anyhting on the ecu fault codes. i am getting shocking economy (worse than the usual disco v8) and told the guy doing the clutch to lean it off.
within the last few days of this new lean driving the car seems to love stalling.
i am at the end of my teather but cant bring myself to sell to beast.
my mates getting me a new coil today but im thinking it could be a throttle position sensor?
Any ideas? please?

 

[tempestv8]

It could be that the engine is not getting a good spark because of losses through the spark plug leads.

Do the following test (but be careful!)

Park the vehicle somewhere pitch black. Maybe try this test at night!

Have ready in hand a spray bottle of water (wife's ironing water spray bottle maybe?)

Start engine, leave to idle. Pop up engine hood.

Spray water in a fine mist around the spark plug leads.

If you get a blue arcing effect coming from your leads, it's evidence that your leads are "leaking" and need to be replaced.

 

[tempestv8]

Oh, and I'm assuming that you've already checked your plugs and they are all OK....

And that you are not losing any coolant....

 

[wolf]

Coil or coil-paks? I am trying to remember if 96 was still distributor or not? I know it changed over, at least in North America in 97, but elsewhere - I am not so sure.

I have heard a TPS going 'soft' will cause this but it should throw a code your way. Does your year have a crank sensor - if so - I would want to check that out as well.

Also, how are your cats and exhaust in general? Again, real issues down there should throw a code.

 

[Disco Mike]

What octane gas are you running, do you have a check engine light on, when was your fuel filter last changed, how about plugs and wires?
When all else fails, you may have a VSS failing which is pretty common.

 

[alsdatto]

i do have a distributor. i think my mechanic replaced some of the leads i can check though for this leaking tonight i have had problems in the past with the leads for the plugs so will check.
it may sound stupid but what is a VSS?
one thing that i dont get is why is it only happening then at 1800rpm.
the only way to get over 1800 rpm is flooring it, but then again this doesnt always work.
i will try everything you've written about so ill keep you updated.

 

[joey]

VSS = Vehicle speed sensor...

Please describe in the best detail you can what is happening at 1800 rpm...

Please include speed, is it in all gears or just Drive you have this issue?

Do you notice the speedometer jumping or going to 0 or anything odd at the same time?

If you go from Drive to 3rd when this happens does it change?

 

[alsdatto]

well the problem only really starts after the car is warm for a while not for say the first twenty minutes of driving say to work or whatever.
what happens is that i will accelerate in either first second third fourth or even fifth and at roughly 1800 rpm the power will just cut out not completely though. if i keep my foot on the pedal the revs drop but only slowly. this can be fixed by letting the revs drop down and putting the clutch in and begin again or by changing upgear and into lower revs. if i am in fourth and the jolting occurs and if i drop it into third i have to put the foot to the ground for the car to go again.
i call it jolting because you put your body into going forwards and then the car drops off so rapidly it feels like the car is jolting.
my mate got me a coil today so ill try that he said its something around that so i might have to get a reconditioned dizzee

 

[joey]

Could very well be the VSS then try unplugging it and see if the issue goes away.

http://www.discoweb.org/vss/index.htm

 

[Disco Mike]

Forgot, you folks, down under, had a distributor on your 96's.
You need to replace all plug wires as a set when doing wires, just as a good rule of thumb.
What octane gas are you running????? Have you ever decarbonded the engine? Have your mechanic check your distributor to make sure the vacuum advance is working.
Let us know how it goes.