hmm... metronome = muscle memory = accuracy = speed...
nagmemetronome na ko... still no speed...
how long have you been using a metronome?
the speed won't instantly happen...
here are some things you can try out when practicing with a metronome...
1. practice without any effects... use the clean channel of your amp... do this throughout your regimen...
2. create a calendar for your speed regimen... remember to start really slow... if you can, start at 40bpm then increase the speed when you can really play those licks you want to play cleanly at that specific speed... again, only increase the speed when you have truly played the lick cleanly... set clear and attainable goals for each day of your calendar...
3. stop practicing for 5 minutes if you feel even the slightest bit of pain...
4. do not do anything else when practicing... focus on fretting and picking the strings right to get the right note... be conscious of your sound...
5. you'll feel very frustrated, sleepy, and bored when you do those things above... but that's what you need to do to get the speed you want... so be patient... breathe in and out when you get frustrated... stop practicing and do something else... then return to your guitar and finish the schedule you made for that day...
i, for one, am not able to play any speed licks... but my goal is not to play faster... my goal is to be able to just play the guitar enough to make people listen and enjoy the music...
good luck!