Do gf perf. chips work on m/benz v8s - 1997 Oldsmobile Cutlass Supreme

Looks the RFDI chip in the key is defect. Your Mercedes car dealer should be able to help you with that.
Fist to make sure it is a chip problem in the key and second by replacing the chip and the code and / or replacing the battery it an empty battery is the issue.

Yes

It is fairly straightforward on the M113 V8s. I can't remember if that automatic tensioner has the 15mm socket spot on it just under the tensioner pulley or not. The tensioner is located on the driver-side lower but next to the power steering pump pulley. Move it from YOUR right to left, when facing the engine and remove the belt. Put the new belt on starting at the crank pulley. The rib side routes all the way around the idler pulley-from the crank shaft, Power steering pulley, top guide/idler pulley and then alternator on the lower right(passenger-side). The back or smooth side goes around the tensioner and water pump.fan pulley. I hope that helps.

do you mean software??? anything after 2005 is encrypted and only the factory has it ,dealers do not have it because they have to connect too the internet to access it direct from the factory.Stops people like me and you from repairing the cars

Hello..
Code 21: Is an oxygen sensor Code 54: Is a crank positioning sensor.
Hope this helps!

In Europe this test must be performed and reset you need a mercedes SDS to reset the light. After that it should stay out for 60 years

try removing the chip first and see what happens

po121 means that there is a problem with the throttle position sensor ( tps). or in the wiring or connector, most likely its the tps that is bad. first remove connection from tps, heres how to test. use an ohms meter and hook a lead to top or bottom terminal of tps. use other probe on center terminal of tps. move throttle plate slowly, if the needle on meter does not move at a smooth pace, then tps is bad. good-luck!!

ask your authorized dealer for ordering the right part,or may check first the fuel pump relay

the rules are this, better airflow throgh the engine equals better perf. run a low restriction filter assembly, K&N and others make them, run a free flowing exhaust, do your research, just because it sounds good that doesn't mean it gives any perf gain, u can also fool with the electronics, they may or may not offer a performance chip for your car, u will have to inquire, call Summit racing, they are one of the leaders in the country on perf parts, they sell the best.