Needing to know where the fuel filter is located on a 1991 Olds Ninety eight

MANY possibilities! Assuming that your security light is not staying on--First, you must determine if it/s a no spark or a no fuel condition and take it from there.....

needs a fuel system flush

There are two ways that i know of to bypass this system. Both are on this link along with info, pics, and other useful info. You CAN fix this yourself.

http://vatspasslockpasskeysecurityhelp.yolasite.com/

its located right behind the pass side tire on the inner side of the frame underneath the vechicle

The spark and fuel both get there reference from the crank shaft sensor , so as long as the crankshaft is turning and the sensor and module are good you will have spark and fuel, it sounds like one thing you are missing is compression I think you should see if you have lost a timing chain, does the engine seam to be turning over at a very fast speed? pull a spark plug and check for compression.....SORRY TO BE THE BEARER OF BAD NEWS

Generally it is the Coils or the ignition control module that needs replacing. Hope that helps.

Gasoline Fuel Filter There are three types of fuel filters; internal (in the carburetor fitting), in-line (in the fuel line), and in-tank (the sock on the fuel pickup tube). CAUTION
Before removing any fuel system component, always relieve pressure from the system.
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Check near the gas tank behind it in the fuel line.

For 1995 Oldsmobile 98 3.8L SFI OHV 6cyl the Fuel Filter is located under vehicle, passenger side, below seating area, front of fuel tank, mounted on frame in fuel line

Hope helps (remember rated and comment this).

I would say try changing the spark plugs and spark plug wires if gas is old put in at least 5 gallons of fresh gas and change the fuel filter.

my fuel filter is located right behind the pass side tire on the inner side of the frame.