No Top End

[Trever]

So i have a 87 ford ranger with a 5 speed and when it get to running temp i bogs down so i was woundering if not haveing the right oil pressur would make it do that because it runs great when cold but when warm it loses all top end any one gat any clues i have do presser test on all valvs and they are all about 150lbs new plugs and wires new roter fresh oil change poped the cats (they were pluged) fuel pressur seems fine

 

[IMenriched]

try to get codes 1st.

if preformance is poor after up to temp maybe the temp sensor is bad ...still creating a over fuel situation after it is up to operating temp. ...IS the tailpipe black ??

 

[Trever]

it was but not any more seince i poped the cats but it runs great till it gets to temp then it drops and its sucking down on fuel

 

[powerplantranger]

Check the timing. Mine kinda did the same thing and for some reason it was 10 deg of time..

 

[ckblum]

I had this issue and I had to check a few things. Ill give you a list of what I checked and you can try the same stuff. Ill try to go in order of least likely to most likely.

Plugged cats
O2 sensor
Throttle position sensor
Clogged injectors (from dirty filters)
Fuel filters
Fuel pump (affected by heat sometimes, especially when older)
Coolant temp sensor (get the brass not plastic)

On mine is seemed like it only did it when it was warm too, but then I realized that I don't really start hammering on it until I'm out driving on open roads like highways and stuff. So you might think it is happening when it's only warm but it could be the manner in which you drive it too. I found that I had to be super light on the pedal to keep from bogging, mine also started to buck sometimes too.