It depends on the location of the vacuum source as they may be beside each other but vacuum source differ
raise the rpm and check if have vacuum you should.
Some vacuum leaks are very hard to detect and a special smoke machine is used to look for it
some shops charge about $ 85 to do the smoke test
check MAF sensor also in some rear cases may give you a lean code
do a fuel pressure test
check for a faulty or clogged fuel injectors
Thursday, October 1st, 2009 AT 6:39 AM