89 Nissan Pathfinder idle hunts from 1300 rpms to 1600 rps

[JLCJ]

I brought my Pathfinder to multiple mechanics they don’t know what’s making my car idle hunt from 1300 rpms to 1600 rps. And when driving down the road it only goes up to 3000 rpms. If I keep giving it the gas while driving it has this bad jerking like it has power and than no power really quick so it just stops at 3000. When at a stop it’s idle hunting and when I go it’s sounds like it’s about to shut off so I shift into 2nd gear and it starts off slow but I have to play with the gas pedal to gain power and sometimes when I’m 3rd gear it will pass 3000 rpms will feel like the power is back and than I shift it than in 4th gear It looses all that power and struggles to get to 1900 rpm. I know I should get a new car but I can’t afford one plus I only payed 500 for it I had it for 3 years. When I got it it had no problems but needed a battery and a tire.

Oh yeah, also my Pathfinder has 337628 miles on it. Also some time when driving I go a few miles and it fells like it is normal but then going down the road I feel it and hear it out the exhaust. The difference in it running great and then it looses power and bogging down and back to playing with the gas peddle to get power to it. Can anyone help??

[Rockwood]

Often high idles are caused by vacuum leaks. So check all your vacuum lines and replace bad ones. If you have never replaced the PCV valve, replace that. Sometimes they stick open. Make sure the oil cap seals tightly. Make sure air is not getting into the crankcase at the dipstick. if you have not replaced the fuel filter recently, you should replace that. Those are inexpensive things to try first.

Here is a thread about a wax pellet problem that causes up / down /up down idle issues:

https://www.justanswer.com/nissan/1bo34 ... up-88.html

If you replace the wax pellet assembly, you must do an idle adjustment procedure.

You should be able to find a video on you tube or a thread on how to read engine computer codes on an 89 Pathy. Try to read any codes the ECM has set. That helps with diagnostics.

Try to find the Chilton manual for your truck. It will have quite a bit of info in it to help you out - Ebay or maybe Amazon.

Fuel pressure could be part of the problem. If no one has checked it yet, it would be good to check it!