I had a fresh rebuild back in May and the car ran fine up until the last couple of weeks when the weather started to get cold. It wants to surge and I can hear a pop (like a small back fire) when I put a load on it (just normal driving) at around 2,500 to 3,000 rpms. When the temp gets up to 180 it seems to go away and run fine. If I let it cool down and go for another drive that same day I don't have the problem either, it's when I let it sit for 4 or 5 days without driving it that I have the problem. Any ideas? Time for new spark plugs maybe? Thanks for any suggestions!
