Sorry if this has already been posted, I searched the problem as best I could.

I have a 2001 4.7L 4x4 Dakota, manual trans, with about 90k miles on it. More and more often when I start the car it won't go above 3000 rpm. I'm lucky if I can get it above 40-50mph. This usually happens for about 10-20 minutes then the truck suddenly gets all its power back and runs like new.

Has anyone had or heard about this problem?

This may or may not be related, but I've also been getting p0031 codes with all my 02 sensors, so replaced them, and my check engine light is still on with the same code on bank 1 sensor 1. Could this have something to do with my frequent power loss?

 

Off hand, what is P0031? What is the name of the problem?

Sometimes the issue is not the components but the wiring leading to the component. ( have a 02 Olds with bad wiring so it throws all sort of bull**** codes. Solved the problem, sort of, bu pulling the check engine light bulb...but that won't work on the newer OBDII cars. Like yours and mine.

I'm trying to get my 97 past acquisition and transfer smog testing (in CA) and have been having a learning experience here! One thing I learned is to not try to splice in a generic O2 sensor...the splice seems to add resistance to the circuit that makes TILT come up.

Still working on that...

 

P0031 is heater circuit low I believe.

I replaced the first two downstream sensors and their codes went away, but the third one that I replaced still throws the 31 code. I'm dreading the idea that it might be one of the lines leading to the sensor. I tried to follow it down and it looks like it will be hell to get to.

 

could you probe the proper leads in the socket? (if you can get the right specs, that is). one of the heater lines (on my n97 I believe they are the two at the top in the plug...the two white wires) should be grounded and the otehr should carry the heater voltage. If it does not show that value within specs, then next would be to look at the other end of that wire...perhaps at the ECU (I recall it is called something else, PMA?)

 

Well I finally broke down and took it to my mechanic. Turns out it was a short on the heater circuit wire on the computer's end, so that's fixed.

The lack of power was because I was getting insane misfires on every cylinder at some point. So now they have to figure out what's causing that. They were leaning towards the idea of the crank sensor malfunctioning. Anyone had problems with that before?

Thanks for your help