I recently bought a 1991 Jaguar XJS. However, the engine is very hard to start and I have to turn the starter for a long time before it finally starts. Moreover, when I put it in D or R range, the RPMs drop and the check lamp comes on. If I don't push it hard with the accelerator, it stalls. Even when I press the accelerator to the max, it doesn't climb a slight hill. Recently, the engine won't start even when I crank it. I thought maybe it was because I was running low on fuel, so I added about 5L and cranked it, but it still didn't start. The panel always shows FF44, but sometimes it also shows FF34. What should I look into?