96 5 spd discovery stalling/losing power at 55 mph
 

hi i have a 1996 5 speed 4.0 discovery. the car has been sitting for 4 weeks without being driven. i have been driving the car for a week now and while i was driving on the highway at 55 mph in fifth gear the motor seemed to have stalled and have lost all power. the motor continued to run while the car was jerking in and out of power(the loss of power was sudden yet smooth but it jerked when it regained the power back). the rover has not done this in any gear except fifth gear at highway speeds.

- would anybody happen to know the cause of this problem?

so far i have replaced fuel pump, fuel filter, O2 sensors, sparkplugs and wires

(also the car does have a burning smell after being reved high or driven hard, im not sure if it is oil however the motor is leaking oil)

all help is greatly appreciated!

The smell might be an indicator - if you had something binding up, like AC compressor clutch, a pulley of some sort, making serpantine belt drag - usually that can throw belt off and make a lot of noise.

You have replaced the usual suspects. The truck has two coolant temp sensors. One drives the water temp guage (AND CAN'T BE TRUSTED), the other is a two wire affair just next to it (just to right of thermostat housing when standing at the bumper) that drives the ECU. Might connect a scanner that can read live data, and see what coolant temp the ecu belives is there, that could vary injector timing, spark timing, etc.

Air filter and air pathway to intake - any critters build a nest?

Some electrical wire loose/corroded on a sensor.

Vac leak - would have to be a big one.

First stop guessing, you are just throwing un-needed parts at it.
Do you have any fault codes?
You most likely have a VSS sensor failing but we should talk before you go thru that expense.
Send me your number and I'll call you.

I was thinking the same thing Mike. Possible VSS on the fritz. Call Mike. Good luck.

So would a VSS going bonkers show up as incorrect vehicle speed on a scanner? Does the ECU think you are going too fast and go into a limit mode?

I also thought about fuel pressure regulator, but hard to imagine that only in one gear.

Miles? Engine running hotter than normal?

As mentioned, try using a good scanner to start.

Yes, that is exactly what happens, the ECU thinks you are going to fast and then starts to cut spark to slow you down, so it will throw mis fire codes.
Usually when it fails it is while under acceleration, like taking off from a stop or climbing a hill on the highway, the truck will lose power and feel like it is mis firing badly.

mileage: 119,500 temperature runs normal check engine light is off
thank all of y'all for the suggestions and yes i believe it stalled under slight accelaration ill go ahead and check y'alls suggestions and get back as soon as i can
thanks!

Mike I need your help bro. 604-710-6924

How hard is it to replace the VSS on a 96 Discovery and where is a good place to get them?