Ford Repair: F150 idles great, shakes and convulses when put in any gear, great shakes, o2 sensors

Question
Please Help! Our 2001 F150, 200,000+ miles is sitting at a mechanics shop and he has recently seen this problem with 2 other F150's but said he doesnt have an answer. Symptoms: Cranks and idles fine but the moment it is placed into any gear the truck begins to shaking and sputtering and then dies after a few moments. Mechanic said that one of the other trucks he saw was sent to a Ford dealership. The Ford dealership said it was a problem with the transmission. Sent other truck to tran shop and the said nothing is wrong with transmission. Please help we need our truck back!

Answer
could have jumped one or two notches in timing have seen this several times and it has ate my lunch too!!--transmission problem is a definite possibility-might try unplugging connector on transmission if it don't die then it is probably trans if it does look for shorted wire on exhuast tube or manifold especially around o2 sensors-clogged convertors-backpressure test can verify this-low fuel pressure-good luck.