My '01 XJR runs fine, except at more than half throttle or going above 3500 rpms. I see that it's likely a secondary fuel pump issue, or at least a general fuel starvation issue. I know where the relays for both pumps are, as well as fuses. I swapped the relays, and the car ran the same, so I think the relays are OK. The fuses are both intact.

The check engine light finally came on, but for some reason my OBD II reader and the one at AutoZone won't connect. The fuses for the ECM seem to be OK as well. I got an error code with my reader, and AZ couldn't get theirs to power up at all.

I intend to start with a filter change, and maybe try to jump the secondary pump with the filter off. Can I use a jumper at the relay with the key in 2nd position, or does it need to be running? Will it come on at all without being over 3500 rpms?

Any step-by-step is appreciated. I'm a fair wrench and have read a lot on the issue, but haven't done anything other than identify the above.

 

I assume this 3500 rpm limit is in park or neutral? If so, this is the ECU keeping you from scramming the engine. If its on the road, then you have a problem.

 

While driving, not in park or neutral.