Hello, I have a 2000 Ranger XLT 3.0 Flex, for the past 5-6 months, I've been experiencing a weird chirping/sucking sound when I go from a stop/slow pace. It sounds like you're sucking a little bit of water through a small straw. The noise only occurs when I give steady gas, then if I give it a heavy gas or ease off the gas, it'll make a slurp sound then go away, and I can go back to a steady acceleration. Although did notice during a trip down south, on cruise control, it would come back for a brief moment then go away at random times. it's the weirdest thing. I did notice that when I was trying to locate the issue, I had the cover off the throttle arm and while the vehicle was running, I gave it a quick turn, and a small chirp could be heard before the truck revved. Could this be my issue, and if so, what could be causing it? I can provide a video if necessary. I've worked out just about every other kink in this thing. Paid 2K for it last year, good shape, looking to keep it that way.

 

Welcome to the forum

Any coolant leaks?
Having to add coolant now and then could mean you are getting air into the system and that will causes noises in heater core in the cab

Could be time for a new PCV Valve, should be changed every 3 to 4 oil changes

IAC Valve has a small black cap that snaps on and off, remove it and see if noise gets louder, if so the valves internal seal is leaking, but usually described as "whistling" noise

The cab vent controls are vacuum operated, i.e. defrost, panel, floor air direction control
Defrost is the default or low/no vacuum setting
turn on fan to high and set panel/floor as the direction, check that no air, or very little, is coming out the defrost vent
Accelerate and see if you feel more air coming out of the defrost vent, if so you have a vacuum leak in the system, could be in that cab or engine bay

 

I do have coolant leaks, though I just ordered a new pump as I'm now getting air in the line which is causing false hot temp readins, which i then have to pull off to the side, crack the cap til the air gets out and it sprays a lil coolant, then recap it withotu burning myself, then all's good (Should also mention I had done a fresh coolant flush and fill about 9 months back, and have added 2 bottles of Bars Leak radiator over the past month and a half, which may have caused a slight blockage). The chirp/suck sound happens whether the air is on or not, and I get cold air and nice heat. As i stated, it onlt happens when the pedal is in a certain range, then when I let off the gas and back on, it goes away. I'll upload a video later of what it sounds like.