Biggest problem is you trying to troubleshoot it, and you dont have the slightest idea what you are doing.
I would take it to a GM shop that you verify has a mechanic with experience on your Saturn and take it to them.
I suspect you need less than $500 worth of repairs by somebody that knows what they are doing but you are trying to fix it in your driveway, but you just have no idea how to diagnose it.
That list of symptoms is typical for a defective map(manifold absolute pressure)sensor.Detonation and misfire due to increased spark advance and a lean fuel mixture,loss of power and/or fuel economy and sometimes even black smoke due to retarded ignition timing and a very rich fuel mixture,poor fuel economy,hard starts,hesitation,and stalling are all typical driveability symptoms associated with a defective map sensor.Check the vacuum hose to sensor also for vacuum leaks and deterioration.The map sensor reports engine load to the computer,which uses the information to adjust spark advance and fuel enrichment.Under low load high vacuum conditions,the computer leans the air fuel mixture and advances timing.Under high load low vacuum,the computer richens the air fuel mixture and retards timing.Fuel mixture and ignition timing will be inaccurate if the map sensors input is hindered from a defective sensor,vacuum leak in hose,or opens and shorts in the map sensors wiring harness
I don't care for your last line. I do happen to be a master truck tech according to the ASE people.
You have no fuel problems you have a EGR valve or a vacuum leak problem.
99 Saturn SL 205,000 miles
recent repairs: new radiator, new fuel filter, new washer pump
My engine started hesitating 500 miles after the new fuel filter. I took it up a hill and I lost a little over 10mph and I assumed lost comprssion, bad valve, all the money pit stuff. Then my dad said to try and replace spark plugs and wires and see if thats a cheap fix. It didnt work. Then a buddy did a compression test and all the cylinders were fine. After checking out a few books from the library we think we narrowed it down to fuel problems. Heres how it currently drives
1.) On engine start my rpms start high and hold for several seconds before falling to normal
2.) Once the engine is warm it hits low rpms at idle and nearly stalls so I hold the brake and give it a squeeze of gas
3.) Hesitation
4.) Low power on hills
5.) Black smoke from exhaust
I called a mechanic shop and took some free lecture on how sometimes all it could be is a bad tank of gas or a fuel filter collapsing no matter how new it is, or the idle control valve, and possibly fuel pump not feeding the engine. So I ran my tank to empty and added premium with some seafoam mixed in and I gained a noticeable amount of power but still a bit under, I also still have problems from the list above. Give me your gold nugget on this "Jacks of all trades but masters of none"
