I am currently dealing with solving some of the similar issues, and will shed a bit of light on what NOT to look for.
O2 sensor.
Air flow meter. I replaced mine with no change in symptoms, and btw, it's more like $250, not $1100!
Possible problems: Vacuum leak. Check all vacuum hoses. Intake manifold leak. Both can cause the surging problems you describe.
Coolant Temp sensor. Also can cause problems. About $30.
OVP. Source of all sorts of evil witchcraft, but related to hot start problems and rough idle. OEM part was deemed defective long ago, and replacement is improved. $65
I would find another mechanic though...$1100 to replace a $250 part that YOU can install in 5 minutes!!!???
So what is an OVP? DO a search and if you have a few days to peruse all of the threads, you will know more than you want to about this little relay.
