Howdy.
Trying to fix my fathers 02 LS with 180k miles.
Car is ok at part throttle but at anything more than half and iy struggles to accelerate.
There is no bucking or poping, no sulfur smell, no smoke.
Acceleration is linear and smooth just very slow. Feels like we are down 150 hp.

I cleaned Throtttle body with spray, change maf with a new Denso unit.
Timing belt last changed at 90k miles, so we are due more or less for another one.

What else can it be? Car is mint otherwise.

Thank You.

 

Usually I would:
1. Run the codes. This is really important and gives a better idea of what is going on.
2. Change the oil. I always use a good grade of 100% synthetic 5-30 weight. Change the filter.
3. Change the air filter.
4. Change the spark plugs. Use an OEM brand. Get them from Rock Auto. This is probably your problem.
5. Clean the throttle body again.
6. Look for vacuum leaks. Go to U tube to find a good procedure for doing this.

Loren