"vibration" RPM,s jumping when hazards are on

[smark]

Ok bare with me, Theres alot of information Sorry! On my 92' f-150 with a E40D auto 4X4 I have been getting this god awful vibration at 70mph and higher that comes and goes everything shakes .I have flushed the trans and everthing was clean,put new cap rotor wires plugs and still there. ballanced the tires three times put on differant tires and sill there,I evevn took it to two differant trans shops and they said the trans was fine it was in the tires. now wouldnt a tire vibration be constant not intermitten? Yes! so its not the tires. Now just the other day i was sitting at the traffic light and my blinkers stoped working and my hazars lights and then just the blinker stared to work not the hazards. so i just let it go thinking the switch was bad. I read some forums yesterday about putting the truck in nutral when its vibrating and see if it changes and no it dose not it still dse it . so just for the hell of it on the expressway I hit the hazards again and they worked but th rpms jumped 500 RPM every time I pushed it almost going into 3rd gear. Could this be part of my vibration problem? or is the pcm bad? there is no codes! Someone please help Im going crazy. Smark

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