I have a 98 Ranger with the famous dual plug setup 2.5L 4 banger. Up until about 1500 miles ago, my truck is pinging very loudly when the engine is cold. After the truck has warmed up for about 5 mins, if that, it goes away and the truck just whispers. I"m not starting what oil to use thread or a ????? vs ????? thread either. I"m running Amsoil Series 2000 0w30 oil.

When the truck is cold, I always give it a minute for everything to get going and then take off as normal. The pinging is best heard when you first start truck that day, or when letting off the gas between 1800 and 1300 RPM coming to a stop. There's no Check engine light on. At idle, regardless the engine is cold or warm, it's silent. Also, I've tried running different brands of gas of the same octane rating, 87. I've tried Sunoco which is my usual place, Marathon and Amoco are the choices in my town and none seem to work or make the truck run any different. I've tried running 89 through it, no difference. Now I've come down to several factors that could be involved here.

1.) MAF sensor

2.) Install OEM filter and ditch the Amsoil filter

3.) faulty sensor or timing

4.) Some excess carbon in the engine.

I've also came up with a few solutions.

1.) Redline Fuel System Cleaner

2.) Clean MAF sensor

3.) Reflush engine with Auto-Rx

4.) Motorcraft filter

5.) Run Premuim Unleaded fuel

What do you guys think, anything else you guys can come with??? Thanks everyone,,,,91

 

I honestly don't think it is an oil issue. Possible but not likely. I would lean more toward an issue in the timing or spark. Not overly familiar with the 4 banger ignition system but additional concerns could be bad plugs, weak coil, bad plug wires (but I don't think it uses them). Could be something also in the fuel system as well but I believe I would lean more towards ignition. You could try a tank with 93 octane and slip in a can of octane boost/injector cleaner to help clean things up a bit.