90 2.9 un steady idle rpm and no fuel pump noise

[happyfast79]

I have a 90 ranger ext cab with a 2.9 and a 5 speed. when i start it cold it idles up and down all the time from 800-1400 rpm . also i dont hear any noise coming from the tank, im guessing thats the only pump it has.

And lastly the fuel gauge always reads empty any easy fixes for that or a way to test if its the gauge or the sender?

 

[Psychopete]

check your fuel pressure if you think it's a fuel problem

 

[RonD]

The cold idle issue could be a vacuum leak, or Idle Air Control valve, there is also an Intake Air Temperature sensor that can fail.

Fuel gauge I am not sure on, may have to drop the tank to test wires.
There is an anti-slosh and gauge sending unit in the tank, if either fails OR has a bad ground the gauge will always show empty.
So you can check ground wires under/behind dash make sure nothing is just "hanging around", lol.
If you can find the wires going to the tank, like in the frame rail, they do have a color code, and you can test the sending unit from there.

Google: 1990 ford ranger fuel sending unit test

Fuel pump is working if you can start and drive the truck.

 

[sjr53]

I just read the codes on an '87 auto with hunting idle at cold start up and got a "41" Running code for always lean. I don't know the fix yet, but soon might. We already cleaned the IAC valve & replaced a filthy air temp sensor first.

 

[sjr53]

It also had a code 33 for the EGR, but don't think that is part of the problem.

 

[RonD]

It also had a code 33 for the EGR, but don't think that is part of the problem.

The diaphragm in the EGR can crack and leak, this creates a vacuum leak and improper EGR operation.
With engine off, follow the EGR's vacuum line to where it connects to the intake, unhook it and use either a vacuum pump or your mouth, to see if it holds pressure and/or vacuum.
Also feel the metal EGR tube for rust holes, you can't always see them.