Have now travelled more than 3000 miles in my Jag since my throttle body issue & it's been perfect. Yesterday however when on a long journey i had a problem. I was accelerating up a steep hill fine then the power just dropped & the car felt lumpy & juddery. I backed off slightly to take some strain off the engine/box & it ran ok. On cruising its fine but everytime I go up a long hill it seems to drop on power & ******/jerk in the transmission (a bit like power on power off the throttle constantly would do). I first thought I had a coil going down but it doesn't misfire stationary & revs cleanly. Any ideas please!!

 

A long shot, but did you have lots of fuel in the tank? Could the steep uphill angle be affecting fuel delivery in some way? It sounds like some sort of fuel starvation issue to me. Maybe check for fuel pressure while car is level and then with the front raised. Maybe some crud in the tank/filter is moving about, causing intermittent problem?

The ****** and jerk in the gearbox would be normal if the revs were erratic, as the car is constantly looking for the correct gear, relative to speed.

 

Fuel pump may be failing, but have you changed the filter?

 

It's got a new filter yes. Could be pump I understand that mileage is common it's done 103k

 

Just an update to say I fitted a new fuel pump at the weekend & it's running great again. Thanks for the info guys it's nice to have someone to bounce thoughts off sometimes.

 

Glad you got it sorted. It's a great feeling to solve a problem and have your baby back up to proper health. Happy motoring and thanks for the update.