Sluggish at 60kmh

[skrams]

My 2000 Discovery is sluggish at 60kmh (40mph) usually in 4th or O/D when gently accelerating. If I step on it it will kick down into 3rd but it almost feels like it does not want to shift out of 4th / O/D.

Any ideas what might be the problem.

Thanks
Stephen

[Disco Mike]

How many miles on your truck, what have you done to it tune up wise, what octane gas are you running and do you have a check engine light on??
Mike

[DevilDisco]

What year is your Disco and how many miles? It may be possible that you have some carbon build up in the engine. I run a bottle of Redline Fuel system cleaner at least once a month and only put in the highest octane I can find which is 93 around here. At 40mph in 4th, I find my RPM's are pretty low and if I want to move quickly I use sport more or manually put it in 3rd to get the performance I want,(you know kind of like driving a manual) You should be able to get pretty good power out of 4th but this is not a high reving engine. I have observed that power for brisk passing maneuvers come in at about 2.5 to +3k RPM's at 40mph you are no where near that.
At higher speeds the vehicle is more brisk and feels lighter but I suspect that's because it's cruising at +2.5k RPMS's at speeds over 65MPH. If the vehicle is new to you take some time to observe how it act's at different speeds and RPM's, and depeding on the mileage it may be time for a tune up(plugs and wires).
Mike is really helpfull but he'll need more info to help yo narrow down you problem. I'm just speculating.

[discofacelift]

Hi Skrams,
I’ve owned my Discovery 2 for almost 2years now and in that time I’ve learned quite a bit about driving it. Firstly they weigh the best part of 3 tonnes and at slow speeds they do naturally feel heavy and sluggish in comparison to the average road car. I find mine goes fairly quick from a stand still up to around 30mph and then doesn’t really find a gear its happy in until it reaches around 35mph when it goes into 4th/overdrive, another thing you have to take into consideration is the gears on the Discovery 2 auto box locks in gear once the gear box senses its been using that gear for some time, which means you will be able to accelerate with out it changing down to a certain extent, giving you the feeling it doesn’t want to change down.
Like DevilDisco says, you can select S the sport mode that will make it more responsive by holding the revs up that bit higher before changing up and will allow the auto box to change down a little earlier, we call that kick down in the UK, even so using S mode will not turn into anything like a road car. If this information hasn’t helped you, I’m sure you will find an answer from this website, there are a lot of knowledgeable people on here and with the rite info will help you.

Regards

phil

[skrams]

Hi guys, thanks for the responses.

I have 128,000kms (80,000miles) in it, I had the plugs changed yesterday, I always use premium gas (92 octane), I use fuel injector cleaner quite regularily, the check engine light is not on, I sprayed the wires last night with a misting of water and saw a couple of arc spots but not many, I will get the wires changed tomorrow, the MAF has been cleaned recently and the air filter has been changed in the last couple of months.

I know it is not a rocket and find that sport mode does not offer any really substantial difference in acceleration. If I kick down it will go, but I have noticed it more sluggish / less responsive than it used to be.

It reminds me of my first car (an Austin Mini) in Ireland. Everytime I would go through a puddle or drive in heavy rain (which by the way is very often in Ireland) it would cut out or almost stall out. A hair drier and an old rag were essenital tools for drying the distributor cap and wires off on a regular basis.

My main worry is transmission problems. I do not need to put $$$$ more into this beast right now.

thanks
Stephen

[Disco Mike]

If it were tranny problems you would know it, there are tons a tranny fault codes that will show up if the tranny is acting up.
I know you have checked your wires but if they are originial, get rid of them cause you probably aren't getting enough spark to really make the old truck roll.
Another thing to be aware of is the Bosch MAF's don't take to being cleaned and you can kill one pretty easilt which will also cause shifting problems in 3rd or 4th.
Mike

[Disco]

I agree with DiscoMike. Change out your leads and while your at it your sparkplugs if they are relatively old. Have a look at them at the same time to see if you have other issues. Road test. If you still have the problem, it could be fuel related. Also, if your catalytic converter is on it's way out, this can also cause your car to run sluggishly.

[imag]

skrams,
why not do a comparison with another Disco II. Try go to a car dealer, look for one that is of similar vintage and test drive it.
The behaviour mentioned by DevilDisco is similar to my Disco's performance. Kinda sluggish at low end, but fairly brisk at 2.5K - 3K rpm.

[skrams]

Originally Posted by imag

skrams,
why not do a comparison with another Disco II. Try go to a car dealer, look for one that is of similar vintage and test drive it.

Hi guys, thanks for the ideas. I will do a test drive of a similar truck as soon as I find one.

I had the wires changed today, drove it and it appears to be much better, maybe a little sluggish still but that might be my imagination too.

DiscoMike, the three amigos have not come back on. It is a week since the codes were cleared. ABS/TC seem to working as they should too.

The mechanic says it might be dangerous not to have the modulator & sensors replaced as I might end up having absolutely no brakes at all with no warning.

Is that a possibility ?

thanks again guys
Stephen (Skrams)

[Disco Mike]

No, that is not at all possible, shows what he knows, worst case you may loose the anti skid portion of your brakes and the traction control but you will have plenty of brakes.
Mike