https://landroverforums.com/forum/di...-vacuum-48405/

I ran across this low vacuum thread in the archives and read all 14 pages, but did not see a resolution. The last post from contrafiddler was, "Ok, disconnected the TPS, immediate start, 18" Vacuum, Fuel pressure 36, Runs smooth about 1500rpm guessing. Depressed throttle, engine skips and sputters. Reconnect TPS, after 10 seconds engine returns to idle 10" vacuum, disconnect TPS idles fast 18" vacuum, disconnect, normal idle 10" vacuum. How do you access the pins to check the voltages with the plug engaged? Mine looks like the GEMS unit pictured."

Did he ever find the cause of the low vacuum and rich running? My 98 seems to be running rich also, although not as bad as his. I have 15.5 Hg vacuum at idle, 19.5 Hg at 1500 RPM, 32 PSI fuel pressure, get about 10 MPG, my before-cat O2 sensors are both running just either side of 1 volt indicating a rich condition, and I still get P1314 and P1313 regularly.