Stop the Engine Chatter...

[stangfan]

I'm not sure what to do...

I have a '96 GT with 80K miles. For the past 5 -10K miles, I've been experiencing what sounds like 'spark knock' at mid-high (3500-6000) RPM's.

When I first heard the 'engine chatter' there was appx. 65K miles on the car. At this point, I could reproduce the spark knock just by 'stomping' on the gas pedal anywhere from 2K RPM's and up.

The first step I took to eliminate the 'engine chatter' was changing the plugs and wires with OEM parts (Motorcraft double platinum). I set the gap according to the manual, and all this seemed to do was move the 'chatter' to higher RPM's (3500 - 6000 RPM's).

I'm 'at a loss'...

From day 1... I've taken great pride/care in my 'stanger. I've changed the oil every 3K miles. I use only Mobil 1 synthetic oil. I've add STP fuel injection cleaner every to the gas every time I change the oil. I only run 93-octane fuel... Ect, etc, etc...

I've even tried to add octane booster(s) to the gas as well as switching the type of gas that I use (BP, Exxon, etc.) Nothing I've tried seems to completely eliminate the spark knock.

I've read a lot about the 96-99 cobra's having this problem but not SOHC GT's. I'm not sure what to do...

Any advice would be appreciated...

 

[Blackgeetee]

You don't need to use premium fuel in your GT. The compression is 9:1 so 87 octane is all you need. That is all I've ever used and the engine runs strong and flawless. I don't know if this is true but I've heard from more than one source that adding fuel injector cleaner plays hell on the fuel filter. I don't know if it was coincidence or not but a few days after I put in a bottle of fuel injector cleaner I had to replace my fuel filter as well as a fouled #8 sparkplug. That so far has been my only problem with my GT with the exception of a worn third gear syncro.

 

[sohowcome]

Same thing would happen to me with my chebbies, they didnt like High Octane Fuel and the higher the mileage got on them the worse it handled the high octane stuff

 

[Blue03Cobra]

You list a K&N, which are notorious for "fouling" the MAF sensor. See my post (about six down) and remember, BEFORE you click on the referenced site you remember to add "disconnect the negative battery cable" before beginning...

Clean the MAF thread

Good luck, I've run 92/3 octane in every car I've owned since 1992. Never had any problems...