1993 need help

Hey guys, I got a buddy who's got a 93 Mazda MX6, 2.5L V6 5 speed, 180K. Has reduced fuel mileage, and sounds like its almost ticking under aceleration. Kinda sounds like its got too much advance, makes this noise from 1000-redline. Alos has a noise coming mostly from the back head, closest to the fuel rails. Hoping the valves aren't cooked, would like any help. Thanks in advance.

ive got a 93 with the same problem... ticks moderately from idle to rev limiter... i put some engine treatment in mine and some lucas oil stuff.. and the tick is quieter now but still there. havent had time to take the motor apart yet but if i figure out what it is ill let you know