Hello rovers
96 Disco 170k, Auto Trans, no codes, runs and idles well. 100% New/oem cooling system,

Every once in a while on the freeway my disco bogs down/looses speed/rpm (approx. a 500RPM loss) for just a couple of seconds and regains its previous RPM. almost like im taking my foot off the pedal at speed. This has be hard for me to diag since it only happens a couple times a weeks. it seems to happen more often during long drives or after the a/c was being used. Im suspecting its either a fuel volume, fuel pump, or vss issue. My evap has been fritzy and im guessing this could be related but have no codes (96 in not advanced evap I know). with the windows down on a drive ill get a strong raw fuel smell coming from the fill neck area. Im pretty sure my fill neck or vent tubes are not venting which I plan to address. My wifes ford got totaled while it was parked by a drunk driver memorial day weekend so we are down to just one car (my disco) I fear a pending failure and then we are really screwed. any help would be very appreciated

Thanks,
Brian

 

I would also unplug the vehicle speed sensor, and try driving without it. Speedo and cruise won't work. When the VSS starts to fail, the ECU thinks you are approaching takeoff velocity and it starts cutting back sprak and fuel to force slow down. This is supposed to happen at 114 mph or so, but a failed sensor does it at more normal highway speeds. May not show up in speedometer due to buffer circuits, but may show up in OBDII scanner. There is a good rebuild thread on it in the forum.