Compression loss, throwing codes...What is it? on 2003 Mercury Mountaineer

My mounty is throwing codes for 4 adjacent cylinders 1,2,3,and 4... The truck runs great when moving, but shakes at idle... its misfiring in all cylinders... had compression test done, and the cylinders are random from 120-170psi.. Uptown auto says they believe its my timing, and I need to replace all my timing components, but they can't tell unless the tear it down.. and that will be $1200 parts and labor... Is this the case, or something else? Im not sure what to do.. I dont want to spend 1200, and that not be the problem.. Thanks

by in Alliance, OH on February 04, 2013
2 answers
ANSWER by on February 04, 2013
Get another opinion, don't sound right!! More likely a vacuum problem, same timing componets for 5,6,7,8 as well so-----!!!
ANSWER by on February 05, 2013
AGREE WITH WETRY. THERE ARE WAYS TO TEST TIMING CHAIN ISSUES