I added seafoam to my fuel tank ( 95 f150 5.8 efi 4x4 160k miles )and then filled it up I then drove home 60-65 mph interstate for about half an hr when I got home it was running better than before and I was impressed because it was running pretty rough before now after 30 min of sitting when I turn the key it buzzes really loud from engine and if I try to crank it itidrains battery and dies .... I'm confused why it's doing this is it because of the efi system?

 

Interesting....
Back to first page to get more eyes on it.

 

Doubt that's related to you using Seafoam.

How long does the buzzing last, and is it only with they key in run, or does it do it in start position too? How long does it crank for before the battery dies? How old is the battery, and did you check/clean the terminal connections?

 

What side is the buzzing on? Could be your fender mounted starter relay. Maybe you blew a relay fuse. I've known to have a couple of those make some noise if they blew out or were going bad.

 

It also may be that it isn't draining the battery but that the battery is shot. The loud buzzing may be the start relay oscillating because of insufficient voltage to hold it engaged, kind of like the starter solenoid chattering but faster. Take the battery to your local autoparts store to be tested. It's an easy and usually free thing to try that will eliminated one potential cause.

I'm with dixie460. I think the timing is just a coincidence.