2002 mazda mpv shifts and drives normally most time. If you are driving at 40mph and let off the accelerator without touching the brake pedal, then try and speed up, the transmission acts like its in neutral. if you hit the brake then try and accelerate. the van will drive normally. all gears feel strong if you start from a dead stop and accelerate through the gears. Problem seems to be when down shifting

How old is your vehicle....most common problem is throttle position sensor...

Workshop / Garage needed to make Diagnostics

check the timing belt

start with the intake system. sounds like a vacuum leak somewhere.

The transmission is slipping, have it checked for low fluid level, if that is ok then you need the transmission rebuilt or replaced with a factory rebuilt exchange unit.

it sounds like a shift lock solinoid ....this prevents the car from being shifted out of park when ur foot is not on the brake....u will have to bring this to a repair shop since the faulty part is located inside the paneling where ur shifter handle is

Probable culprit would be the electric solenoid that releases the gear shift linkage when you apply the brake pedal. Since it's electric, a dead battery will cause the same result. Check to see if your brake lights are working. If not try replacing your brake light switch as this also gets power to the above mentioned solenoid.

This is a safety feature to prevent children from accidentally putting a car in gear.

Good luck!

down the dipstick tube!!!(really)DO NOT OVERFILL...
Your audi is fitted with a fuzzy logic gearbox, it will change according to your driving style.TRY THIS,put into 1st and without touching gas pedal, let the car accelerate to top gear,stop Then using onle 1/3rd gas pedal do it again.then using 2/3rds do it again.then only using the minimum pedal req accelerate to max legal limit.(try not to use brake pedal,let the car slow down itself,until you have to)then drive as normal, it will feel like a different car.

The term "shift lock" is the system that is in place to prevent the vehicle from being shifted out of Park into Reverse or Drive WITHOUT having the driver's foot firmly on the brake pedal. The brake light switch on the brake pedal closes a circuit that energizes a solenoid under the shifter. When the brake is applied, and the solenoid is energized, the shift lever is no longer "locked", and can be moved to the desired position.
The idea here stems from a phenonomon several years ago that dealt with the issue of "Sudden Intended Acceleration". What was happening here was, for some unknown reason, engines started developing high RPMS for no reason, and several accisents were reported due to this issue. The vehicle would accelerate "unintendedly", when putting into drive or reverse, and could hit something.