If I use the key in the ing. the starter sounds like it's working really hard to turn eng. over and turns over like the timing is off. Checked timing, batt. and ground connections, installed new ing. modulator. Can jump start selonoid and turns over fine, only when I use key switch it turns over slow and labored. Should I install a new ing. switch and is that the same as the key switch in the colunm? Oh yea I forgot, this is a 1992 4.9,300 6cyl. with a 5 sp. man. trans. Thanks.

 

I suspect your problem may be the clutch safety switch.(I found that to be the problem in an old tractor). Then I would try the ignition switch as you suggested. No, the ignition switch is not the key tumbler, it is below that. I would get a Haynes repair manual for your model truck.