1993 Buick Roadmaster

Engine Performance problem
1993 Buick Roadmaster V8 Front Wheel Drive Automatic 194000 miles

Seemingly random, my '93 Buick Roadmaster will have acceleration issues where some days I will have an excellent rate of acceleration, and other days it can't seem to push past 2000 RPMs unless you stomp on the gas pedal. Spark plugs and wires have been replaced, fuel filter changed, and a new muffler and catalytic converter have been replaced with minor improvements to performance; however, the heart of the issue still seems quite prevalent. Is this just the car being so old that it is slowly dying or is this just an smaller obscure problem? Thanks for the assistance.
June 7, 2010.

Have you checked fuel pump pressure? Has the check engine light come on?

I have not checked fuel pressure; however, no check engine light has come on. Lately, the idle on either cold or warm start (seems to be 50/50) will not come to idle properly. It will walk back and forth in between 500 and 1000 RPMS, then after a minute or two come to proper idle. The throttle positioning sensor checks out okay as well as the coolant sensor. There are no vacuum hose leaks that I or anyone else has been able to find, and as far as I can tell, the fuel pump is either going to work or not at all. Start-ups on the car are consistent. I have never had an instance of the car giving me a hard start yet.

Aug 26, 2010.
The idle is odd and usually indicates a bad idle air control valve or throttle position sensor.