Hello to all! New to this forum and new owner of a beauty of a ride. Last week, I purchased a 1990 Ford F250 extended cab, 2-wheel drive with a 7.3 IDI. This truck is a monster and in excellent shape and only has 150,000 miles on it. I hadn't started it since I bought it last Friday, but when I went to crank it last night, it had trouble firing. When I turned the key and waited for the light to go out, I noticed a loud clicking. It turned over several times, before finally starting after the fourth attempt. I drove it around the neighborhood and after that, it started several times with no problems. This morning, I went to crank it again. This time, I got the same clicking noise, but it started on the first try but idled kinda sluggish for a little while before settling into a smooth idle. I'm thinking this might be the glow plug relay switch or perhaps the glow plugs themselves. The clicking noise made me think it might be the relay switch. Does this sound familiar to anyone? Thanks, in advance, for the advice!