Help! Advise Needed

[S1NRR]

Had my Tuscan S for just over a month and love it but.......when Im on the motorway and doing 80+ the car feels strange like it is hesitating very slightly or its like theres a heavy head wind and thecar is really working hard to push trough it Hawthorns have had it in twice and it running perfect.....the only thing I can think of is that I have never had a car that creates its own down force could it be the splitter on the front / fin on the back that pushs the car down / back and making it feel this way.....if its meant to do this then fine but until im sure im going to worry its a problem thats going to damage the car in the long term...Danny

[qualityscrew]

Had this problem with my last Tuscan - but it didn't appear until 7000 miles. It seemed to be affected by ambient air temperature - If the weather was hot the problem went away, but in cold weather it got worse.

[donaldhunter]

I also have this problem with my Tuscan and I'm trying to identify if it's temperature, fuel or something else related. It really bugs me so I'm keen to find a solution.

[S1NRR]

Donald, Have you tried Optimax, I havent yet but Might give it a go......what has your dealer said about the problem have they checked it out???

[donaldhunter]

I'm trying to run exclusively on Optimax but occasionally have to fill up elsewhere. I suspect it could be temp related. The dealer has looked at it a couple of times but we need to carry out a more thorough investigation.

Cheers, Donald.

[donaldhunter]

It feels like the ECU is varying the fuelling based on a slightly erroneous input to me. So in theory it should be possible to diagnose by watching the sensor inputs using a dealer's diagnostic computer. But it means warming up and going for a fast run with the computer hooked up.

[S1NRR]

Donald,

I will keep working with my dealer on the problem as well.... my email address is on my profile so you can keep in touch what is the best way to contact you if my dealer finds the solution, it would be great if can both work on this one....

Regards

Danny

[joospeed]

whenever I've seen this it's always when the mixture is trimmed weak on the lambda control .. weak mixture = slow burn = less torque.
You can get the MBE ecu to target a richer mixture which would cure it, but the factory are unwilling to do that, I've never had any success trying to bluff the lambda sensor outputs either. I would think you're stuck with it if it's still there after the dealer has tried all his tricks.
Only options are as far as I can see :
emerald / dta / omex / other aftermarket ecu
piggy-back an interceptor unit that can modify the lambda outputs.

[s2art]

I've noticed the same thing but its very slight. If you put your foot down there doesnt seem to be any problem. I wonder if its deliberate, seems unlikely but is the ecu detecting persistant light throttle running and leaning off the mix as far as it can? I was surprised to get approx 30+ MPG on my S recently on a long motorway run at speeds between 80 and 90 so something is working well.