oil pressure ...going crazy

my oil pressure gauge in my 88 coupe is going crazy on me.....

it will bounce around.... stays within the safe range but it jumps aound.... i noticed my belt tensioner has alot of slack and is jumping a lil bit...


could this cause my oil pressure to jump a lil ?

if so i need to change this tensioner soon dont i ?
 
Same thing here. My oil pressure gauge would bounce around like mad. $11 and 5 mins later it was fixed. Oil pressure sending unit. Incase you dont know, it is the cylindrical looking thing that screws into the head on the drivers side right near the firewall.