1997 buick Lesabre studers when driving over 50

https://www.autocodes.com/p0756_buick.html

https://www.autocodes.com/p0107_buick.html

Most likely the fuel pump is worn out electricially or
binding & stopping mechanically

Change the Filter and Fluid in the Transmission and see if this helps. If it doesn't then you will need to have the transmission serviced at a shop.

check the fuel pump

Possibly a plugged catylitic converter. This can cause to much back pressure and that will cause the engine to run poorly under acceleration or loaded conditions.

If it knocks at 50 it will knock sitting still if you race it up. Is the oil pressure good? These motors hardly ever have a bearing problem. The only knock problem was the harmonic balacer that comes apart and knocks. The rubber falls apart and it will make a knock sound all the time, more with the ac on. If you have a knock at 50 or highway speed only you may need a outer tie rod end only. Get the front end checked as they will make a knocking sound on the highway. reply

remove plugs and check for carbon tracing . if found plugs and wires will fix problem

Overdrive is for highway driving for better gas mileage. Good Luck

they have had alot of problems with key switches in that model that is where i would start

Hi! If it seems to be much worse in the rain, why don't you have a mechanic test your engine for codes and functions after he rinses your engine down with water? Water won't hurt your engine. Good luck! Jack