1998 GT

when i get to around 55-60 mph and my rpms are close to 4000 something in my engine makes a crackling sound. Does anyone know what this could be? if this helps my car is a 98 GT automatic. Thanks

ryan1994mustang

why are your RPM's that high at that speed? i am not positive about the 98 autos, but my 94 gt manual is only at about 1500 RPM's when im at 60mph. not sure about the crackling sound, but that may have something to do with it. is your transmission not shifting into overdrive?

1998 GT

sorry i shouldve said that it only happens when i get on it and not all the time just between 3500 and 4000 rpms and yes it is shifting into overdrive. when im just cruising at 60 im a little under 2000 rpms

ryan1994mustang

it could be sparknocking from bad fuel or low octane fuel. try running a tank of mid grade or premium gas in it and see how it does.

1998 GT

i normally run 89 octane but i might try running some 91 or 93 octane and see how it does and thanks