I'll give you some background info just to clear things up.

I feel I'm a pretty solid improviser, I've always been able to pick up and go. Generally when I improvise the scales I use are the pentatonics, the blues scale, a cross of the two and I generally try to stick in some melodic and harmonic minors just to shake it up a little bit. I try to use modes while improving but I find that harder and it's one aspect I'm working on. When I improvise, I know what I'm playing, in my brain I can here the melody that's going to come next, so I'm not just playing random notes. The problem is that lately I've noticed that I hear that the melody I'm singing in my head is a repetitive one I seem to have created and always end up coming back to. Now whenever I improvise I have to concentrate to make sure that I don't stick it in by accident, because if I did it's not really improv anymore. That annoys me because I'm so focused on not playing it, that my improv is deteriorating because I'm concentrating in a different way than I used to.

Here is my question. Does anyone know how I might be able to get out of this? I've tried improving with the major scale but for some reason it sounds empty, don't get me wrong I love the major scale, it seems to lack substance. I've also tried improving in a different style, with different time signatures and keys but it all seems to be pretty formulated as well. I hope this is good enough and that you don't close it night .
Learn as many licks from as many different styles as possible that you like and try to incorporate them and use them as a base for further improv. Another idea is to do a solo in a different style to what the piece is in, give it a different feel, and perhaps different improv ideas.
Founder of Jaco society

[22:08:23] <Confusius> I wish I was a bassist
[22:08:26] <Confusius> you fuckers look cool

Want to know how to play bass in jazz? Read this.
That reminds me of something. CowboyUp, you don't need to tell me to learn solos by my favourite artists, I've seen you posting it so many times I started doing it a while ago
Start playing some jazz standards. Their harmony will make it so the melody you are hearing will not fit. Try something far out there.
Don't tell me what can not be done

Don't tell me what can be done, either.

I love you all no matter what.
This problem could probably be due to a couple of reasons, I'll try to address the most likely ones.

Chances are is that this melody that you play is a "mommy melody" of sorts, one that you can always run to if things are turning out quite right, and this isn't necessarily a bad thing to have, but you don't want to become dependent on mommy, because it shows, and it doesn't look very good. The ladies have never been keen on the mommas boy type.

I have two theories as to why this melody has become a habit, or your mommy melody. One is that you may haven't have actually grasped or familiarized yourself with all the harmonic capabilities of the scale you are using. Or two, that you have lost the adventurous creative improvisational spirit that is oh so important.

I suggest you do the following. To further familiarize yourself with the scales in which you are using, just practice developing new melodies within those scales. It's simple, and it works and if you find some that you really like memorize it and you'll begin to develop a little "library" to call upon when things are bad. As opposed to having just one mommy scale, you now have many! Also the cool thing about improv is that you can take one of your old ideas and rehash them, making it into something entirely new by just adding or subtracting two notes and/or changing up the rhythm a bit.

In the event you've lost that adventurous spirit inside, well, it's kind of silly for me to try to tell you how to obtain the ol' mojo, but it's really just a state of mind which you just kind of have to acknowledge the existence of the infinite harmonic capabilities and really go search for that unique and interesting something, whether it be a rhythm, harmony, or melody.

Finally, since you cited your inability to make something of the major scale, you may need to relearn, or learn for the first time, how to construct a melody using chord tones and triads. I never approve of people diving straight into the modes without having a strong base in chordal improvisation, they seem to think 7tones are better than 3 or 4. You'd be surprised what you can do with 3 or 4 notes.

So yea thats the skin and bones of a lot of basic improv techniques. Each one really deserves a small book. (and for some they exist!) Hope that helped a bit.

P.S. In the event that non of the aforementioned scenarios are applicable, nor any of the practice ideas fruitful, fire your accompaniment because it's probably their fault.
Not even a backing track?
My name is Andy
Quote by MudMartin
Only looking at music as math and theory, is like only looking at the love of your life as flesh and bone.

Swinging to the rhythm of the New World Order,
Counting bodies like sheep to the rhythm of the war drums
"Sheets of Sound". Get that book. It WILL solve your problem.

The way I see it, your fingers will tend to do what they've been trained to do and
what they do most frequently. If you don't make youself do NEW things in practice,
your improv will start to sound the same -- you'll be wearing a rut in the floor so to
speak. Remember, when you're improvising its as much, if not more, about motion
than it is about melody.

So, what's "Sheets of Sound"? Basically its a thick volume of interesting pattern
studies and movements. Most of it is diatonic movements given in the major scale,
but they can also be easily applied to melodic and harmonic minor. Back and forth
and upand down the fretboard. Linear Patterns. Intervals. Arpeggios. Sweeps.
Economy picking. Hybrid Pickins. It's all there.

This book has put more new content into my improv than anything else I can think of.