Power loss problem

[Odin's Chosen]

I just bought my second ranger an 87 4x4 5spd and been driving it for 2 weeks now but in the last 2 days I noticed that it will lose power when I put in 4th or 5th. I can have my foot all the way to floor and nothing happens the rpms don't go up and my speed won't change. Ive done a little searching online and come up with a few ideas but nothing really concrete. Any help is appreciated.

 

[sjr53]

Since '87's don't have a check engine light, you should first read for error codes. Other than that, I would first check fuel pressure and ignition timing.

 

[RonD]

Could also be exhaust system is getting plugged up.

Vacuum gauge can show you if it is, $25

Read here: http://www.gregsengine.com/using-a-vacuum-gauge.html

It can tell you alot more as well, very good tool to have in the box
No matter how many things they add, or change, on a gasoline engine it is still just an air pump so how a vacuum gauge reacts will give you needed info