rough idle...pinging?

[Exrange]

My mother has a 94 explorer with the automatic. recently it has been running really rough at idle, has lost a lot of power and is pinging. The thing that i don't understand is that it only pings and runs rough somtimes. I've replaced the plugs, wires, fuel filter, cleaned the MAS and the filter with no improvement at all. Anyone got any ideas what could be wrong? It has 110k on it. Thanks, Matt

 

[ExplorerSPL]

I would run codes on it, i think you can do it without a code scanner, however thats how i've always done it, I ended up having a bad MAS, I cleaned it and still had problems, it still shows code for below minimum MAS voltage.. or maybe yours will say whatever your problem is, at least point you in the correct direction, search here for running codes and see if you can do it using a codescanner.

 

[CBoug76]

Just curious, but what Octane is your mom using? I Know my 97 Sport requires 87 Octane, otherwise it will ping, Mileage will drop, and its Bad for the Pistons, Carbon will build up on them. so make sure she is running with 87 Octane!

Chris