4 litre power loss problem

[TroyM]

93 ford ranger 4 litre 5 speed

problem: engine loses power between 1000-3000 ish RPM.

what i have done: cleaned the K&N filter, installed new fuel filter, checked cat converter, it is good. I have cleaned the MAF sensor with the MAF Cleaner.

when it happens: on any startup, whether cold or hot, it runs perfect for about 20 seconds with lots of power, then after that it feels gutless and sounds like its wanting to go but cant. If i turn the key off while driving, then turn it back on, it will be good again. Then after 20 seconds of driving again it starts losing power.

so what is it? MAF sensor needs replacing or o2 sensors, fuel pressure regulator?

thanks.

 

[TroyM]

ok so i disconnected the MAF sensor and its still doing the same thing... runs good for about 20-30 seconds then has no power and bogs again

this has all started happening right after i pulled and replaced the 5 speed tranny. maybe the o2 sensors got full of crud from when i used the impact to take the exhaust off??

 

[TroyM]

so during the tranny replacement, i unplugged both oxygen sensors. i noticed one plug was painted red by someone. on the right side. red=right

after install, i plugged them back in, not remembering that red for was for the right side sensor.

i just switched them and the truck runs perfect now.

i would have thought that it would make no difference as they are both the same plugs for left and right.