I have a y reg mondeo 20l petrol had new plugs leads lamber sensers new speed senser on gearbox . every time i try to speed up when the revs get to 2000 it cofs and spluters anb wont get power

One, the sensor uses two wires, this plugs in close to the sensor and one might be loose or came loose. Two, you need to replace the sensor. Sometimes the wires break off at the sensor. See on the side of the gearbox.

not likely some cars have a nylon gear around diff but dosent give trouble often. try fuses, wiring and clocks in that order

on the gearbox, between cockpit and engine. On the gearbox are only 2 sensors. one for reverse lamp, and one for speed.

In the engine compartment, you will need to locate the transmission dipstick. Usually on the left side of the motor, labeled "Trans fluid". Pull it out and check the fluid level. Your problem could be as simple as putting transmission fluid in it. That will make it slip. You fill the transmission right down the dipstick tube.

try puting heat resistant shield between inlet manifold and exhoust manifold could be evaporating when hot

Well the same thing happened to me a few months back with the exact same car but what i noticed was when i was changing the spark plugs one of the HT leads had come off the spark plug so i fitted new spark plugs and re-fit the HT leads properly - Problem solved :D

hi
remove the speed senser from gear box and put trans oil in . this is only one way if u dont have filler plug

I had this exact problem on my old focus. Its nothing to worry about and its not expensive. Your car has a speed senser underneath the gearbox and a common fault on these cars is for the gearbox to slightly drip oil. When the oil drips it drips right on top of the senser and blocks the speed readings.
The good thing about this is your milage on your car wont go up when the speedo stops working, so when you come to sell it!!!!!!! you get my point.
to fix this problem it cost about £20 if you do it yourself.

I had an Audi doing exactly the same. What happened was that through time, especially if the vehicle gets older with a higher milage, dust and dirt gets into the speedometer itself and causes all the small gears to get sticky. I opened it and lubricated all the small moving parts inside and all were ok. Try it before buying a new speedometer. (I'm talking about the speedometer clock itself) Hope this info might help.
Akirfa

give some details like how much your car had run in miles.

hows you drive at speed which speed.

THNX