1994 Toyota 4Runner

Engine problem
1994 Toyota 4Runner V6 Four Wheel Drive Manual 187000 miles

I have gone through basic tests to find the problem including oxygen sensor, and catalytic coverter replacement. I have had no luck. It has plenty of power at times, but every so often power drops significantly. It allmost acts like its vapor locking. I replaced the fuel filter and it ran fine for about 15 miles, and started acting up again. When its acting up the more throttle you give it the more it slows down. Could my pump be going out, or is there some sensor I've failed to check that could cause this problem? I would appreciate any feedback. Thanks!
December 7, 2007.

Hi. I have the exact same problem and same model. Have you diagnosed the problem? Any help would be greatly appreciated. Cheers.

Jul 1, 2012.
The engine diagionstic scan will show up any problems with a fault code, you can also check live data while the engine is running and check that TPI signal is correct I would be checking this first, a qualified mechanic on hand to read the data and interpret the readings will be a great assistance as unqualified persons can misinterpret reading easly.

Jul 1, 2012.