Hesitation in '05 LR3 SE?

[bureau13]

I have a question for those of you with more time behind the wheel on these vehicles. It seems that when starting from either a stop or slow roll, when I press the gas pedal there's a bit of hesitation, considerably more than I would expect from a V8. I used to get a similar feel from my old Volvo XC90, but it was a 5 cylinder turbo, so it didn't surprise me. With the LR3, it feels different...its not so consistent, and just feels sluggish. Once the engine decides to open up, its got plenty of power, its just not instant. I can mitigate this somewhat by putting the tranny in sport mode, but it doesn't seem like I should have to do this. Anyone else notice something like this, or do I have something going on with my truck?

jds

[Evil_speedracer]

I have a few questions, is this between 2 and 7 MPH and when you decelerate and then accelerate are you getting the little slam? These things have the fly by wire throttle which takes getting used to if you are used to cable setups, its not quite as responsive. How many miles? Have the plugs been changed? Are you only using High-test (premium) fuel? How long are you going between oil changes?

[bureau13]

Its more like if I'm off the gas, either stopped or a slight roll, and then I press the pedal normally there is usually a pause where it does very little. Its given me a start several times where I judged that I had a small window of opportunity to merge with traffic, and then had to really gun it to get moving. Once I do that, it winds up pretty good, but its the part throttle response that didn't seem quite right.

The car has had all regular maintenance, its close to 30K right now, and the last oil change was not very long ago, maybe 28K or so. I've actually been using the mid-grade stuff lately...there's no missing or pinging full out, and I thought octane was simply a measure of resistance to pre-detonation? This really hasn't been a recent development, it seems that its always been that way, maybe a bit worse recently or maybe its just my imagination.

jds

[Roverdude]

I've had similar occurences in my 03 Freelander and other modern cars. i think a major part of it is the electronic throttle often tries to second guess what you're trying to do. never happens on my 91 RR w/ the good old fashioned throttle cable.

[Evil_speedracer]

These trucks are to sip premium only. If it is hot outside, is it as little worse? That could indicate a knock, and the hot ambient air along with midgrade would cause enough knock for the ECU to pull a little timing out. I am not sure about if these run on copper plugs, but th eservice life for coppers is about 30,000 miles. I am about to change mine as i have noticed the idle is a little rough compared to the "is this thing even on?" smoothness I had before. Otherwise, it is most probably the fly by wire.

[bureau13]

I will go back to the premium and see if that helps. My experience with lower octane, even when not recommended, has been that either there is no difference (sometimes the ECU will pull timing to accomodate this although I have no idea how it knows) or any detonation problems occur mostly under high loads, e.g. wide open throttle types of situations. Of course, none of these experiences were with Rovers, so maybe they don't apply. This definitely feels like a throttle problem to me...if its the nature of the design, then IMO that's pretty unacceptable.

I'm trying to remember what I did at the last service, and I don't think plugs was one of those things, so that's a good input. How hard are they to get to on this vehicle? The dealer seems to charge an arm and a leg to do ANYTHING that's not covered under warranty.

jds

Originally Posted by Evil_speedracer

These trucks are to sip premium only. If it is hot outside, is it as little worse? That could indicate a knock, and the hot ambient air along with midgrade would cause enough knock for the ECU to pull a little timing out. I am not sure about if these run on copper plugs, but th eservice life for coppers is about 30,000 miles. I am about to change mine as i have noticed the idle is a little rough compared to the "is this thing even on?" smoothness I had before. Otherwise, it is most probably the fly by wire.

[sideview]

Doesn't sound normal bureau13. My V6, although no race car is pretty peppy on the throttle from stopping start...hesitation & sluggishness I've only noticed in full throttle when overtaking. Keep in mind too that the transmission is adaptive & tries to learn your driving style. I think that every time the computer gets reset it has to re-educate itself

[bureau13]

Uh oh...I've honed my driving style on Mazda rotaries...press it to the floor and don't let up til you get where you're going! I'm getting close to my next service appointment though, so I think I will mention it and see what they say.

jds

Originally Posted by sideview

Doesn't sound normal bureau13. My V6, although no race car is pretty peppy on the throttle from stopping start...hesitation & sluggishness I've only noticed in full throttle when overtaking. Keep in mind too that the transmission is adaptive & tries to learn your driving style. I think that every time the computer gets reset it has to re-educate itself