The speedometer and the tacho have been lagging a bit after I left the car in the airport's outdoor long term lot for 7 days straight, where it doubtlessly got the crap baked out of it each and every day in this heat wave. After about 15 minutes of driving the tacho got back into proper working order, if you discount the wonderful ZF tranny's clunky shifts, but the speedometer has been lagging about 5 to 10 seconds behind my actual changes in speed. It has improved somewhat over the past 12 hours, but its still lagging about 5 seconds and any speed below 10mph is displayed as 0.

All other gauges working fine.

Yes, the speed sensors themselves have been giving me trouble as of late, but no lights are on right now and I'm not sure that this would account for the tacho being lazy for a while.

Anyone else experience this sort of thing? Would greatly appreciate any advice you guys can offer!