Hesitaion 3.9 95 Disco

[Wrdherm]

Hey guys kinda new to the rover thing have 2 of them and try not to bother people but my 95 has developed a hesitation under power and it feels like its beginging to surge going down the road like at 2000 rpm have installed new plugs checked the connection at the fuel pump wondered about the tp sensor and the stepper motor also have replaced the fuel filter.....and was also wondering if anyone knows what the fuel pressure should be at the rail idleing and running at a good rpm so i can rule out the pump any help would greatly be appreciatied I am in Chatham Va ......thanks ....Robbie Ward

 

[_carson_]

When was the last time that your rotor/cap/wires were replaced? Type of plugs? How many miles on the truck?

 

[mainerova]

may try cleaning the vss?

good luck

 

[MUSKYMAN]

at idles the pump should produce about 30-33psi then jump up to about 35-38 psi at speed.

cap rotor plugs and wires are important but you should also check all the vacume lines to make sure manifold vacume isnt bleeding off.

you should also take a vacume pump and check the vacume advance on the distributor. the diaphram can crack and then they dont advance anymore and that will cause a hesitation as you roll on and offf the throttle.

 

[Wrdherm]

I am wondering what is the correct way to clean the Vss sensor and should I wonder about that stepper motor.

 

[archaeology_student]

Check the leads... had a similar issue. Turns out one was melted through and shorting/arcing on the engine.