help please electrical problem

[bowanna03]

i had a head gasket job done a week later allof sudden my gauges are not working the oil pressure and volt gauge work but i have no speedo rpm gas gauges and when you try to move in first gear the truck doesn't want to move almost feels like its not shifting i changed the batterie checked all grounds and all fuses all harness's i don't know do you think the computer would be bad please need help it has a 4.3 in it