I have tried just about everything. I have changed the ignition module, coil, spark plugs, cap, rotor, wires, Cam Sensor, Cat. Converter, transmission (twice!). I still have the same problem.
It starts fine. When I start to drive it the motor just bogs down and is very sluggish. I couldn't even make it up the driveway! Then sometimes it will drive fine. But only for a short time. Then it has no power again. I thought it was a transmission not shifting back down. I changed that twice. I thought it was a weak spark issue.
Any advice would be very appreciated.
Thank you very much for any help.

 

Exactly whatare youtalking about a car? a truck?Year, Make, Miles????????????????

 

Have you tested the fuel pressure?
When was the last time you replaced the fuel filter and air filter?
Are you getting any codes?
TPS could be going out?