Look for a solenoid under the fan shroud with an open nipple. Its either an SAS solenoid vacuum line or a purge vacuum line.

Unless the PO capped off the other end , you will have a vacuum leak and unmetered air which will make for poor running.

What a steal for $300! The hesitation near idle sounds like vacuum leak, I would first inspect and/or replace all of the 20 year old rubber vacuum lines and make sure there are no uncapped nipples etc, then see if the hesitation is still there. Does not sound like a MAF issue, FWIW. Dozens of people...

Besides ensuring a battery or alternator isn't near-dead -- alive enough to start the car but dead enough to cause dash lights and a 1000 other weird things -- I can't think of a more important Stage 0 item than vacuum lines.

You can save a good money (get down to to half the price anyway) on the PCV job by (1) clean out and reuse the oil trap box, it is just a near-hollow plastic box and (2) for the large hose, fashion one yourself see posts by user tryingbe here on the MVS forum. Only the funny shaped hose from the oil...

It is not, sorry!