Hi
I am proud owner of a 1984 XJ-SC 3.6 Manual, however unfortunately not very mechanically minded. Unfortunately it is not running very well and I am having little success of a cure. When accelerating the engine often cuts out and I have to pull back and try again, feels like the engine is cold or fuel not getting through. Initially had someone to retune, which wasn't the problem, he highlighted that when idle gas reading 1.5%, however at 3500rpm 10% which should be 0.5%. He suggested, Fuel Injection Coolant Temperature Sensor - which I replaced, no change, and ECU, which I sent to Blue Streak who repaired the pressure sensor, still no change.
Any other ideas, gratefully received.
Thanks and best regards
John

 

If those figures mean the car is running very rich, I would suggest leaking injectors or maybe a throttle position sensor not functioning correctly

 

I have a similar car with similar problem. In my case when I accelerate car often does not start accelerating right away. Sometime it makes 'coughing/farting' sound for a moment and then takes off. Getting off pedal and back sometime help, but no always.

I replaced TPS to no effect.

If yours is loosing power during acceleration, one of the things to check is fuel filter. If it is getting clogged - it may not keep-up with quick demand for fuel causing power loss. In theory same effect can happen if fuel tank ventilation is not working creating vacuum in the tank (rare, but happens).

 

Thanks for the posts. Will give them a go.

 

Does it do this after the car has gotten warm?

I seem to remember that could point to a failing Ignition Amplifier. Perhaps those more expert on the Lucas system can chime in.

 

Unfortunately no difference once warmed up.
Thanks