I am using the Evolution TPS that comes on the Alpha trainer.
I have been using it for several months with no problems, but lately it has been acting up.

It will start up and run great for about 45 seconds and then just die without warning. I dont think its to lean because there is plenty of smoke coming out of the exaust. The last six flights have been deadstick landings.

I have tried different glow plugs and that did not work.

I have noticed some small air bubbles in the line between the remote needle valve and the carb
so I removed the tank and inspected it and the fuel lines, but did not notice anything wrong with either. Are a small amount of air bubbles acceptable?

I have tried tuning the high end and then removed the limiter on the low end to tune that. I could not get it to transition within the low end needle limiter settings. It would load up and die most of the time.

I had it transitioning perfect in the garage high end sounded good and it idled nice and didnt sag when going to full throttle.

I took it out to fly today thinking the problem was fixed, but it started acting the same again. It would load up,so I would lean it out then it would run fine ,but die in the air.

It seem like this engine runs fine in the garage, or when the temperature outside is warm, but when it gets colder it wont stay running the temp today was around 30.

I need some suggestions I am fairly new to engine tuning, and this is the first time I've had trouble with the Evolution. I have had several of them with no problems.

I am afraid of removing the neddle limiters and getting it too lean.
where would be a good place to start over with the needle settings?

My fuel is almost one year old could that be the problem?

I hope I am describing this with enough detail to diagnose the problem, if not ask me a question and I will try to answer.

Any help would be appreciated.