2003 Saturn Vue grinding noise

A few mo. Ago I had a reduce power light come on limped home turned off & restarted my car no problem happened a 2nd time I checked the spark plugs, replaced them as well the coil, About 3 weeks ago when I started the car had a grinding noise for a few seconds it went away, The SES light came on while driving, I replaced the coil pack / distributor it got worse, asked my oil change guys the looked at it thought it was the timing belt they did not think so when I picked it up the grinding noise is loud & I can feel the engine miss, they do not do engine overhauls, one guy thought it might be a barring inside the engine they put it on there diagnostic machine, came back with fuel too rich intake air too hot, the question is try to repair or have it replaced both are expensive. Terry