I have a 2001 Ranger 4x4 with a 4.0. About 1500 miles ago I started having a noise from under the hood that sounded like a shield of some kind was loose. It only happened between 2500-3000 RPM. I searched the whole engine compartment and found nothing. I tried a can of octane boost in a tank of premium gas. Quieter but no help. Tried a bottle of injector cleaner. No help. I took it to the dealer since it was still under warranty and they said it was the belt tensioner pulley. WHAT?! I took it to another dealer and they said the pulley was ok, but I was using gas with too high of an octane. Too high !? Uh ok. I tried what I thought the problem might be, injector cleaner and octane boost. Anybody else with some suggestions?

I'm no where near informed about the subject of timing, but if the engine were pinging or knocking, wouldn't it happen at all rpms, not just the ones you described? For that reason, I believe there is something loose, whether it be a fan shroud or the idler pulley. If the truck is under warranty, get them to fix it for free! I'm not sure about the 4.0 but you should always run whatever octane the gas cap says to use. Running higher octane than stock is for cars/trucks with advanced timing. Don't know if this means without the advanced timing it will retard timing, but I do know you should always stay within specs. I use 87 for my 1996 2.3L. - HB frdrngr01

Hello, I also have a 98 ranger 3.0l engine pings like hell under any load. Dealer could find nothing. Do know if there is any recall on a 98? Tom.

I have a question for ya, is your truck manual or automatic? I experianced some clutch chatter in the 90 model I used to drive. There is very little you can do about it, i just turned the radio up...lol I have a 2k1 now and I hear a little noise under the hood but its the bearing on the tensioner pulley, again, radio drowns out the noise.

It is an automatic. I would take it back and tell them to keep it until; the noise is fixed and not just gone, but they have blown me off and bs'd me till it is out of warranty. I am gonna contact Ford and raise the BS flag, cry wine and moan until they give in and fix it. As someone said, love the truck, hate the service. CHUCK