Momentary Loss of Power

[Augustinaris]

Okay, I've had a problem for a while on my 1987 2.9L v6 4x4 Ranger. So here's the situation... When I start the truck, it runs how it should, with no problems. I can drive it, or whatever, but a few minutes later, the rpms drop, and there's definitely not as much power. If i don't drive anywhere, I can see the rpms drop, and if I gently push on the gas, not much happens...the rmps go up not very smoothly, and sort of jump around...but when I push far enough down on the pedal, where it should be high rpms, the rpms all of the sudden jump up.

And so this problem occurs just a few minutes after starting up. Just having the truck run, the rpms drop a little, and sort of hover up and down, and then....like nothing ever happened, the rpms go back to normal, and the truck runs perfectly fine after that. Also....When the rpms first drop(when the problem starts), I can turn the truck off, then right back on, and it's as if the problem wasn't even there.

I'm really stuck On this one...as to what the problem could be.

I pull the codes, and Get code 31 and 41....EGR Valve Position sensor below minimum voltage, and O2 sensor reading rich.

I wouldn't think the EGR valve position sensor would cause a problem like this....but does anyone have a clue as to what the problem could be?

Thank you a lot In Advance!

 

[n_grimm]

One possibility is you are loosing your spout connection intermittently. That would cause the ignition timing to retard to about 10 btc dropping rpms and power. I have had a bad tfi do the same once it gets warm. Good luck. Norm

 

[Augustinaris]

One possibility is you are loosing your spout connection intermittently. That would cause the ignition timing to retard to about 10 btc dropping rpms and power. I have had a bad tfi do the same once it gets warm. Good luck. Norm

That is exactly what it feels like. I disconnect the connector, and start it, as if checking the timing, and it feels exactly how it is acting. I've tried cleaning the connector, but it still does the same thing. What is weird, is that it's not a non-stop issue...it happens intermittently. I've got to look at the wiring soon.

 

[customrangers1]

im interested in this too. mine has been doing this since i bought it. does yours also do this both on a cold start and a warm start?

it only does it once and only for about 30 seconds.

 

[Augustinaris]

im interested in this too. mine has been doing this since i bought it. does yours also do this both on a cold start and a warm start?

it only does it once and only for about 30 seconds.

I don't think it does it when It is at normal operating temperature start, and yeah, it does it for like that long, and then doesn't happen again. Sometimes it doesn't even happen at all, and I'm stumped. I've replaced so many different sensors, I've looked for vacuum leaks, and I can't figure it out.

 

[customrangers1]

mine always dose it warm or cold just after its started. i just wait for it and hold the gas till the rpms start to take off then i go

 

[Augustinaris]

mine always dose it warm or cold just after its started. i just wait for it and hold the gas till the rpms start to take off then i go

When it happens to me, I just do that, or just let go of the gas, and restart the truck. How is your EGR system? I was told to check that, I know my EGR system is fine...Other than my Pressure Feedback EGR sensor(pfe) AKA EGR position sensor. I think that is bad on my truck, but haven't gotten around to checking it. I know it leaks air...and I don't think it's supposed to.

 

[customrangers1]

me egr valve is still on the truck but isnt hooked up. if mine leaked, wouldnt it run funny all the time?

 

[kaifretz 612]

mine always dose it warm or cold just after its started. i just wait for it and hold the gas till the rpms start to take off then i go

I have an '88 2.9 v6 auto and I've had this same problem since I've had the truck, and I do the same thing just wait for rpms to level out and go.

 

[kaifretz 612]

Coustom1- do u have the same engine; the 2.9 v6 auto?

 

[customrangers1]

yep
5 speed

 

[kaifretz 612]

Crazy, I set up to have my codes pulled so we will see if any thing turns up from that.
Any others having or had this problem?

 

[customrangers1]

bump

 

[83rangerdiesel]

I'd try disconnecting the 02 sensor so it will stay in open loop then go drive it and see how it acts. Sounds like once it goes into closed loop is when it starts acting up witch makes me think the 02 sensor is bad.

 

[customrangers1]

my o2 sensor isnt hooked up, would it go into closed loop within 5 minutes of starting?