Cant print anymore. I must be snake bit

Ok i have another weird problem. I am using Pronterface and Slic3r 8.2 and Sprinter firmware. Never had this problem before so i dont know whats going on here.

If i connect to printer with pronterface and set the temp to say 170C it will heat up to temp just fine. If i load a sliced g-code file and hit print, it will heat up to about 2 degrees below the target temp and then drop a degree or two and then just oscilate between those two temps without ever reaching teh target temp so it will not start the print. I have my slic3r set to 180C for first layer and 165C after that. But when heating up to run a part it will reach 178C and then drop to 177 maybe 176 and then reheat to 178 again and just get stuck in that loop. Everything was running fine yesterday, i dont get it.

I just ran a print and it wouldnt go, so i stopped everything, i manually set the target temp to 185C and when it reached the temp i hit print. It loaded the file and then took off and printed just fine. Just wont reach target temp in auto mode.

I fought this problem all day. Still have no resolution. I re-downloaded Pronterface, same problem. I re-downloaded Sprinter and uploaded the firmware and again, same problem. So i connected the printer to my cad-cam computer and whoala, it ran fine first try. I only had time to run one print so i didnt get a chance to retry multiple times to see if it worked consistently or not. But once again im stumped. Why do i get all the weird problems nobody has ever seen before?

So here i go again. I connected to my laptop that i use to run the printer with and same problem. Stops within 2 degrees of target temp and will go no higher. So i disconected and hooked up to my cad-cam computer and it did the same thing. So its not the computers, its definately something with my firmware or hardware.

What the heck could cause this?

Hmmm...

Not knowing anything about the type of hot end you are using makes it difficult to diagnose the problem.

One thing you said is interesting. You say you loaded a sliced gcode file. If you sliced it in the past, then the temperature is hard wired into the file. Pronterface will not try to over ride what's in the already sliced file.

If this is the case, that you are using a file that was previously sliced, just re-slice it.

If not the case, tell me more about your hot end.

I found the problem, just didnt post it, my bad.
The problem turned out to be the fan blowing to much air on the hot end and cooling it to fast. I forgot that i had opened up my fans nozzle to allow more air to blow. After disconnecting the fan it works fine everytime. I just have to make sure the fan is not running when the print is started, once its started the fan can run and the hot end will keep up.