Has anyone heard of any problems with the manual pump on top of the assemble that the fuel filter screws onto not working to prime the system? I have an '02 Duramax with 150Kish miles and this winter I've had the thing not start 3-4 times. Each time I've gotten out, pumped that manual pump until tight and then it started right back up and hasn't been a problem until sporadically appearing again. Then this past Fri. this happened again, but I could never get the system to prime how it has in the past, and thus, I couldn't get it to crank. I live in SC so real COLD is not a problem. But coincidentally when this has happened, every time but 1, it was in the 20s and once in the teens. One other time it was 35. Do I need the block heater below 32? Is that causing the thing to not crand and/or lose prime? Doesn't seem right?? I recently had the fuel filter changed and noticed this filter was not even hand tight where it screws into this assembly I'm referring to with the pump on the top. Could this have let air in the system and the pump just doesn't work anymore? I took it back and they put another filter on it, but still couldn't get it to prime. It has been last spring since I had the fuel filter changed before and this problem showed up a few times before this last filter change. Anyone heard of cold causing this type problem, or Chevy having a problem with that manual pump going bad. Guy that got it running again said he had to disconnect air intake and hit with a little ether to get it to crank. Drove it. Sat over 2 hours then it fired right back up again. I've also changed the fuel filter myself before and I almost never got it primed back after that to crank. Took 20 minutes of pumping that manual pump with no resistance, and then it finally got resistance and then cranked. I'm scratching my head here. Hate to go back to the dealer and their labor rates without some insight. Anybody seen this or can help out. Tks.