I'm calling upon the collective wisdom of the Jaguar Forums because new management took over my favourite Jaguar shop and fired all the old guys who actually knew what they were doing. The old guys would've been able to solve my problem, but alas these new jokers spent a whole day with my 05 XJ8L and still couldn't figure the problem. Here goes:

Started noticing the car was a bit more sluggish than usual. Soon after I got the Check Engine Light, along with a rough idle and Restricted Performance that comes and goes, but the CEL and rough idle never falter. The new yucksters read the codes as the fuel trim lean codes (can't recall the exact code #). They perform smoke test...no leaks. Replace air filter...no luck. He suggested replacing the spark plugs and coils, but as I have no faith in him, I just took back the car.

A week ago, the car shutters hard on ignition, but calms down after a few moments. Today, the car simply died immediately after ignition. I turn the key and give it some gas. It shutters for a few moments and resumes normal operation.

From what I've read here, I've decided to first clean the MAF sensor, then change the spark plugs, and if that doesn't work, it could possibly be the fuel pump. Does this sound like a fuel pump issue? What else could be at fault? Surprisingly, there aren't many Jaguar mechanics in Los Angeles, and I dread having to take the car back to that guy. Any input would be immensely appreciated.

 

Is it the same whether hot or cold engine ? The two main feeds to the ECU for fuelling are (1) engine temperature, and (2) ,mass air flow. The rest are just trims, i.e small adjustments to reduce fuel consumption and improve driveability.

 

Wish I could help you but I don't know much about the "R." I think it has two fuel pumps.

Eddie

 

It's not an XJR, its just a regular old XJ8L.

Yeah, the CEL and Restricted Performance come on whether the engine is hot or cold. However, it seems to only perform its shuddering-upon-ignition act if I'm out and about, starting and stopping the engine several times.

 

Now that I think about it, the stalling at ignition has only happened 2 times, and both times I had had the radio on for at least 15-20 minutes prior to starting the car. Could it somehow be battery-related?

 

It doesn't sound like a fuel pump problem to me.

I had a fuel pump problem on my old Saab-it idled ok but when you put your foot down to accelerate it shuddered-fuel pressure too low.

Mechanics check this by connecting a pressure gauge to the fuel rail to measure pressure.