I have an 88 pickup sas, on 37s. All of a sudden it started bogging out and being sluggish in 3rd gear. Most of the time it's fine if I'm at a dead stop then stay on it threw the gears, but if I just slow down and try to get back on it starts to bogg out untill it hits 3000rpm then it's like someone hits the nos button and it just takes off!! Just replaced the fuel filter and it didn't help at all!!! Any help or pointers would be very appreciated!!!!

 

Sounds to me like a burnt valve or vacuum leak...I would run a compression test 1st (always good to start trouble shooting there) then inspect for vacuum leaks (they can be hard to find!) Also, hows the 02 sensor?

 

Actually my 02 sensor just dangles around and I don't have a cat. I live in an area that I don't need to pass DEQ and when I bought the truck it was already like that but ran fine for months.... Untill now!!