After 16 years of owning the XJ, decided to walk on the wild side and do a little upgrading from stock.

Upgraded to 703 injectors last night and reset PCM. Hard to say whether it was the 703's themselves with the 4 hole pattern or just the new o-rings that really smoothed out the engine (Didn't really realize it was idling rough, before!). Those injectors are for sure quieter than my stock ones, though.

The stock injectors had been on the vehicle since it was built in 1996 and came out covered in filth and crud but the business ends at the tips of each one were shiny as new. Never had any injector issues the whole time I've owned the XJ. Some of the o-rings were more like hard plastic than soft rubber. The dirt and grime must have been sealing the ports for all I could see. Mpg was holding at 21-22 all the while with the stockers.

As for the 703's performance, I'm just going to have to monitor mpg, seat of pants performance, etc to see how they will do over the longer haul. I've seen conflicting reports on the forums but so far they seem to work well. Don't know how much more mpg they can provide since I was already pretty much at the upper range for an XJ, anyway, unless I want to get into all that weird hypermiling stuff. Not my cup of tea.

My $.02...

Already thinking of some kind of mild lift project...