I have a 15W GE Helical (FLE15T3/2/D) that seems to have a weird problem.  We bought it new in a 4 pack and put it in our 3 lamp bathroom fixture along with another one and a smaller Sylvania 13W.  After a while the ballast started to pop and crack and sizzle, as if it were going to die or burst into flames (this lamp gets hot), and the tube would flickr at maybe 50-75% brightness (I don't know really, not good a judging that) for around a week off and on a continued to go from a few little spirts to lengths of time.  So I took it out and put it in my desk lamp, immediately, same thing.  A day later I put it in a "socket on a cord fixture" (looks like a genaric no name brand, but looks well made and works well (40W rating)) and it worked great with not 1 issue, used it for hours at a time for maybe a week and it would shine at full brightness, I stuck it in another "socket on a cord fixture" (I don't know if they have another name) that is vintage and it also worked.  Stuck back in the bathroom, immediate flickr a sounds again.  I just now stuck it in a ceiling fan, same thing.

My question is, why is it doing this?  The only thing between the fixtures is the fixures it works in are not regular lamps ("sockets on a cord") and the others are (for lack of a better term) porperly made fixtures that stand on their own (or hang).  The first "socket on a cord" also had just one metal strip this sticks up into the part where it screw in instead os one metal screw lining.  All of the plug in fixtures have 2 prong plugs and the grounding for the other fixtures is unknown.  Could it just be a grounding issue?  We live in a pretty old house and a lot of it is ungrounded.  But the other 3 CFLs work fine, and every light in our house.  This is the only CFL we have had that has not worked right.

EDIT: Just tested it in a floor lamp for a short time and it worked (plugged into an outlet strip).

Probably poor lamp to lampholder contact on the center conductor of the Edison screw base. If this is the case the crackling and popping is the arcing made by the poor contact.

It could be one of the wires in the base of the bulb is loose, so some sockets hold it tight and others are loose. Most of these CFLs have the neutral wire pinched in the base with no solder, so it could be a manufacturing flaw.

Wow, thanks!  That sounds like it is the answer!  In my desk lamp is I unscrewed it a little, it started working immediately!  Same thing with the ceiling fan!  The bathroom light, not so much.  Thanks!

I encountered this problem many times in the past, both with incandescent and CFLs on sockets with poor contacts (The contact lowered too much inside the fixture, so it not make a good contact with the lamp base). CFLs flickered like the incandescents, but made noises of arcing. A flickering as a result of a bad contact can kill CFLs in minutes, unlike incandescents, which immune to this problem.
All you need, is to lift the contact inside the socket of your fixtures with a screwdriver (Screwdriver with a plastic head. never do this with a screwdriver with a metal head, because of the risk of an electric shock) so it will make a better contact with the lamps bases.

I encountered this problem many times in the past, both with incandescent and CFLs on sockets with poor contacts (The contact lowered too much inside the fixture, so it not make a good contact with the lamp base). CFLs flickered like the incandescents, but made noises of arcing. A flickering as a result of a bad contact can kill CFLs in minutes, unlike incandescents, which immune to this problem.
All you need, is to lift the contact inside the socket of your fixtures with a screwdriver (Screwdriver with a plastic head. never do this with a screwdriver with a metal head, because of the risk of an electric shock) so it will make a better contact with the lamps bases.

Bad contact is also a leading cause of premature incandescent failure as well.

Why that bad contact in the socket would lead also to a premature incandescent lamp failure? Incandescent lamps aren't sensitive to brownouts and turning on/off as CFLs. The flickering of CFLs on bad contacts at the socket, put stress on their tube electrodes and ballast electronics. Incandescent lamps haven't any thing to being stressed by this flickering.
Bad contact don't causes an overdriving (The only thing that shorts the lifespan of incandescent lamps), so the life of incandescent lamps shouldn't be shorted as a result.

Why that bad contact in the socket would lead also to a premature incandescent lamp failure? Incandescent lamps aren't sensitive to brownouts and turning on/off as CFLs. The flickering of CFLs on bad contacts at the socket, put stress on their tube electrodes and ballast electronics. Incandescent lamps haven't any thing to being stressed by this flickering.
Bad contact don't causes an overdriving (The only thing that shorts the lifespan of incandescent lamps), so the life of incandescent lamps shouldn't be shorted as a result.

I don't know the failure mode, but a bad lampholder is something electricians know to check for in a case of rapid failures.

Reason why bad contact on incandescent is the heat to the stem press cause it break the seal on the lamp

I encountered this problem many times in the past, both with incandescent and CFLs on sockets with poor contacts (The contact lowered too much inside the fixture, so it not make a good contact with the lamp base). CFLs flickered like the incandescents, but made noises of arcing. A flickering as a result of a bad contact can kill CFLs in minutes, unlike incandescents, which immune to this problem.
All you need, is to lift the contact inside the socket of your fixtures with a screwdriver (Screwdriver with a plastic head. never do this with a screwdriver with a metal head, because of the risk of an electric shock) so it will make a better contact with the lamps bases.

But other lights have worked in those fixtures, the same exact model CFL has worked in the same socket in our bathroom fixture.

Also the flickering problem was one that did not start in the begging and progressively got worse and now it does it like crazy until you unscrew it a little.  I haven't left it on too long because of risk of fire, failure or breakage (if it can happen).