Hello All;

I have a '98 F150 with the 4.2 in it. Recently it has started pinging. It happens when under load at the time that the IRC opens. When that happens I get a 1/2 second of rattling and then it is quiet again. My suspicions are that the air flow sensor is dirty and allowing the engine to go lean momentarily when the IRC opens, OR, an oxygen sensor is starting to go and causing the lean condition, OR, perhaps an injector or two are getting dirty and not delivering a full load of fuel into the cylinder. I have also noticed that sometimes on a cold morning it has a miss for a few seconds on start-up. If anyone has any thoughts or opinions on this problem, please pass on the knowledge. Thanks.
Glenn.

 

Try 89 octane. My truck will do fine during the warmer months with 87. But when the colder weather gets here, it starts to ping a little. 89 octane always works for me.

 

If you read your Ford manual you will see it reads, there is going to be some pinging upon heavy acceleration,hill climbing,etc. It also reads that your engine was designed to run on 87 octane gas only. By using a higher octane gas you are only masking possible problems that are occuring or that can occur.
Try cleaning your throttle body.Also,add a bottle of Techron fuel system cleaner,or a can of SeaFoam to the gas tank. Some people like to use BG44K.