Surging power

[rkbrown13]

I have a 89 ranger 4x4 with a 2.9. It starts and runs fine for the most part but periodically I can feel it lose power but then a couple seconds later it will be back to full power. It seems to me like a fuel problem, I changed the filter but it is still doing it. Any suggestions would be great.

 

[87Ranger4me]

I have the exact same problem with my 87 2wd and have been looking for the solution for two years now. I have replaced most all the sensors and still no joy. I seem to notice mine surging the most when I just start to climb a small hill, if its a big hill and you give it more gas it seems smoother and on level ground it runs pretty good. I'd almost swear it seems worst when running Ethanol gas also. I'm sorry I don't have the answer, but at least I know what you are talking about, and will be watching this thread for a answer myself.

 

[CraigK]

Try disconnecting the O2 sensor. Not changing it, just disconnecting it.

This instantly solved the cycle of sputtering and outrageously bad mileage I was experiencing with my '87 B2. This problem plagued me for YEARS (it gets much worse over time), and I don't want to tell you how many perfectly good parts I replaced before yanking off the O2 connector . . .

If this stops the problem (it will be running slightly rich with fairly crappy mileage in "open" mode with the sensor disconnected), then try changing the O2 sensor. I would not recommend changing the O2 sensor if you have significant exhaust leaks.

CraigK

 

[rkbrown13]

Mine mainly does this at low RPM's probably between 1500~2200. I will try disconnecting the O2, its worth a try.

 

[spdcrazy]

mine started doing that but only after she got warmed up a bit.. come to find out it was because a few of the electrical connections got wet from playing in the river. i was outta town on a job so a buddy just disconnected them. wiped them clean, and left them disconnected for a day or two. put them back together and bam.... she runs great.

 

[rkbrown13]

I disconnected the O2 sensor and the problem went away. Should I put a new O2 sensor in now or just leave it?

 

[CraigK]

If you do not have any other significant or obvious problems, I would try replacing it. But, if like me, you have a significant exhaust leak upstream of the O2 sensor (that would disrupt O2 sensor readings), I would recommend waiting until the problem is fixed.

CraigK

 

[rkbrown13]

Actually I have no exhaust leaks.

 

[dwhite]

mine did the same thing, and it ended up being the timing was off 30* because the harmonic balancer wore out and slipped so it was impossible to time correctly until i replaced it