I'm having a rough time with getting the car to highway speeds. Once the car gets to 50MPH, i can put the gas pedal on the floor and the car doesn't accelerate. Today I had a rough time with accelerating from a red light. Where can I look for possibilities as to what is causing this? Fuel filter? Is my throttle cable stretched?

 

How resent was your last tune up including a throttle body cleaning, particularly the screen? Could be as simple as a clogged air filter.

 

I've never had one done on it. I did have the intake tube off and I inspected the TB. It looked clean. What could possibly clog my air filter? How much would a tune up be for a 2000 LS?

 

I don't know the history of your car or what conditions you drive it in, but the general rule of thumb is to do a tune up every 100,000 miles, some things sooner depending on the type of use. One of those things is the air filter which clogs with particulates in the air. I would definitely replace that if you never have. I change mine every 30,000 miles.
Depending on the definition of "tune-up" A shop might charge $200-300 depending on what they do. I would also recommend a transmission fluid and filter change if that hasn't been done. Add $150-200 for that. And another $100 for an EGR passage cleaning, a common problem with 3100 and 3400 engines.

Here's a link to a thread covering a 100,000 mile, and regular maintenance:
https://montecarloforum.com/forum/fw...0-miles-46078/

 

Acceleration problem solved...the throttle cable sheath was obstructing the throttle body from opening all the way. Once I put it back where its supposed to be, the throttle body was freed up. While I was at it, I also cleaned my MAF sensor as well.

 

Gotta love those zero-cost simple solutions!