I just want to check to see if I'm reading this correctly - Your saying that it's an issue with Google Maps, and not the GPS framework/hardware? The cache is causing this after 4 to 5 days of use?
This seems like an issue with the HTC stock rom on the Sensation. If this really fixes it, I would report this as a bug to HTC & to Google. Right now - I have 3 Google phones and 1 tablet in my house (MOTO OG droid, HTC Thunderbolt, HTC Rezound & Transformer TF101). All are running custom ROMS except my tablet, and I don't have this issue with any of the phones or tablet using Google Maps, Google Navigator & Google Latitude on a consistent basis.
The app your showing a picture of »
play.google.com/store/ap ··· 0dXMyIl0. has helped with my Thunderbolt & my tablet. After clearing the GPS data, and downloading the data, I get a lock between 10 and 30 seconds. I've never had to clear my map data or cache.
There have been plenty of reported issues with Google maps - but as a relation to getting satellites to lock in - it has always been reported as a hardware/framework issue...
**Edit** - After re-reading, you stated that you are flashing a ROM, so it's possibly an issue with the ROM you are using.....