Help, 1991 4-runner, loss of power, strange

My 1991 4-runner has a loss of power. The best way I can describe it is; it looses power like the A/C unit has a huge drag on it, going from normal to lackluster, and then back to normal, except it does it with a/c unit on or off. It also gets lousy gas mileage now.

I have been told that I should replace the Throttle position sensor, and I have read of intake air leaks.

I just wonder if anyone has had this same. "lack of power, regular power" interval situation ???

Thanks

you might check your pcv valve( if you have one, i don't remember) you might also check your fuel filter as well.

(Damn Jake, this post is almost 2 months old...)

Check your EMC codes:
http://www.off-road.com/toyota/tech/codes/
http://www.autoshop101.com/forms/h27.pdf

If no codes show up, I would start with testing the ECT sensor, then others related to the fuel management system. Don't just buy new ones, test the old ones - and their wiring. Could easily be a loose or bad connector.

See the following articles:
http://www.autoshop101.com/forms/h20.pdf
http://www.autoshop101.com/forms/h21.pdf
http://www.autoshop101.com/forms/h22.pdf
http://www.autoshop101.com/forms/h23.pdf
http://www.autoshop101.com/forms/h24.pdf
http://www.autoshop101.com/forms/h25.pdf
http://www.autoshop101.com/forms/h26.pdf