MaconBoyTahoe

I have a 1999 Chevrolet Tahoe that I purchased a week ago, because it's the only thing that I can afford for $1,300. I have a full time job, and my wife does too, so it's tough to be picked up, anthenopped off at work with 2 children in school, and one being mentally disabled. I know that I'm blessed to have my family, and I'm just asking for some kind regards about why does my Chevrolet Tahoe will not run unless number three spark plug wire is disconnected? I tried a new plug/wire, but with the same result. If anyone can explain why this happens then I will be so appreciative! Thanks, and God bless. Dennis Macon