86 ranger idles but dies down when given gas

[pnut F]

i have a 86 2.9 that idles at about 1400 rpm. fp is 35 psi. when pressing the throttle the motor dies back, let off, idles good. cleaned iac valve, cleaned the air sensor in the middle of the throttle body, cleaned all plugs in wiring harness. replaced all vaccum hoses.

 

[Psychopete]

i have a 86 2.9 that idles at about 1400 rpm. fp is 35 psi. when pressing the throttle the motor dies back, let off, idles good. cleaned iac valve, cleaned the air sensor in the middle of the throttle body, cleaned all plugs in wiring harness. replaced all vaccum hoses.

Can you go more into detail about how the motor is dieing back? I am not sure if you're indicating that the RPM is dropping, or if the engine is actually dying out for a sec. After that, is it fine?

 

[pnut F]

its more like no fuel or air fuel mixture wrong. it does have a slight rough idle. if i un plug the iac, the idle smooths out and the rpms go to 800 - 1000. if you hit the throttle with the iac unplug the motor will stall. open for ideas / thought and knowledge.

 

[keebler]

I know you checked the fuel pressure, but did you check it while you were pressing the gas pedal? Only reason I ask that is because I have an 86 ranger that I just had to replace the fuel pump in the tank, today. Idling, I could push the gas pedal and it would hesitate alittle bit, but would run good. If it just idled, it would run ok most of the time, but then sometimes it would rise in rpms and others it would be low rpms. While driving it, i could feel the truck, not getting enough fuel and then getting enough, but could barely tell that. Changed my fuel filter and then it wouldnt prime. Just put a tank fuel pump in it and it solved all my problems. Its a thought

 

[kimcrwbr1]

erase the memory on the computer and disconnect the battery for 1/2 hour then run it at medium speed for 20 minutes and run the codes while the engine is still hot. Then go from there.