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Re: When accelerating from a stop, car lurches when...
On a lot of vehicles there is a transmission speed sensor that receives data that tells it how fast the car is going and shifts accordingly. If this sensor is bad the transmission can't function properly. I would have this checked, they are not that terribly expensive, and not that hard to change on most vehicles. Hope this helps.
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This process must be carried out in normal mode (not sports mode). On a
flat road, the transmission fluid temperature must be above 60° C (140°
f) and below 100° C (212° f) (vehicle at normal operating temperature
will ensure that the transmission fluid temperature is above 60° C (140°
9. Accelerate from rest with
light throttle (do not exceed the upper rev limit in appendix 1). 1-2,
2-3, 3-4 shifts must occur with engine speed between the following
limits:. Note: Do not move the accelerator pedal during shifts.
10. Continue to accelerate gently to 50 mph (80 km/h) so that transmission shifts into 5th gear.
11. Go into overrun and let the transmission shift down into 4th gear without braking.
12. Brake gently to a standstill and hold footbrake on for at least 15 seconds.
13. This process should be carried out at least five times.
Page 2 of 3 Bulletin Number S307-17 ________________________________________________________________________________
the engine tickover is too slow when the engine is cold its running on cold start, ie:choke,, after it warms up the engine slows down this is what is causing it to stall in gear,, get some one to hold the brakes hard on and with the engine running in gear ajust the tick over till its reving at 750 - 850 rpm the revs will go up a bit when its out of gear,, before you pick a gear to go into push the foot brake down to stop the car lurching,,,
I have a s40 1.9d / 2000 plate,
In the last month or so the car loses revs when changing up to 3rd and 4th gear, I can only get 50 mph max in 3rd gear 80mp in 4th.
The car has just clocked 185,000 miles
Its a great car but a pai at the moment, I've had a service including fuel fillter change added fuel cleaners to the deilsel all to no avail
Quick check is to accellerate from a stop with steady even pressure on the gas. Watch the tach. It should have a good shift at approximately 2000 rpm and the tach should not jump higher during the actual shift (called flairing) This should be the same for each shift. Converter lockup (4th gear shift) should cause tach to drop about 500rpm and should happen at about 45mph. Then repeat the same process using a more agressive acceleration. Shift points in rpms may be a bit higher but each shift should not flair. To check lockup, while driving at about 50mph, lightly touch brake pedal and you should feel ti disengage for a moment. Since you have an opportunity to return it, It would not be a bad idea to get a hands on evaluation from another shop you trust...I can't see it from here and a live person is better equipped to give an informed opinion.
one unit that operates ratio changes and is connected to the engine is that vacuum operated actuator on the transmission
it is possible that that unit is failing , vacuum hose is leaking and that will cause ratio changes as the vacuum varies
run the fault codes to check for wiring problems or VSS or TCM problems as well