Hey guys,

Lately I have been noticing some issues and I'm looking for some feedback on what it could be. Here are a few things I have noticed. Since I have owned the truck at about 2600 RPM's it makes a noise like a belt slipping on a pulley but recently has gotten worse to the point where it does it at 2000 RPM's. I pulled the belt off and it still makes the same noise. Camshaft Synchronizer you think? This is the second 2001 with the 4.0L that I have had that has done this. Another issue is that as of late I have been getting horrible gas mileage down around 8-9 MPG, and I was throwing the code "PO171 System Too Lean Bank 1", I replaced the elbow hose under the upper radiator hose to the PCV valve and it hasn't thrown the code since but the gas mileage stayed the same. At idle with the hood open I can hear it hissing and at about 65-70 MPH it whistles, and the brakes sometimes lock up. I'm thinking another vacuum leak somewhere. But the issue I have noticed the most is a clinking noise from under the hood at idle all the way up to 93 MPH. I looked up videos on youtube to compare it to pinging but its something completely different. It sounds like a metal clip rattling on something and I put a belt tool up to the valve covers, alternator, A/C compressor, Power Steering pump, heat shields, and I can't pinpoint where its coming from. Any help is greatly appreciated guys!

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2001 Ford Ranger w/ 4.0L SOHC V6
255/70R/16 Tires
K&N High Performance Filter Charger
F-150 Suspension Setup