98gt detonation issue

[thad]

i have a 98gt completely stock minus mufflers and a drop with 67k miles...and it has started making a pinging noise at high rpms (4.5k and up) i think its detonation...but i dont know why it would be detonating the motor is complety unmolested and just had the 60k mile tune up done at the dealership...any ideas

 

[duff daddy]

Check your fuel, if needed drain and flush the fuel system and try again with new known good fuel. see how it goes.

 

[thad]

i put premium in it but it still detonates

 

[reivaxtorres]

check the fuel pressure....could be that the fuel pump is going out and its starving the motor. could also be that the fuel pressure regulator is acting up....could be clogged injectors......could be a vaccum leak...


test the fuel pressure and go from there.

 

[duff daddy]

i put premium in it but it still detonates

Not the GRADE the QUALITY octane rating means NOTHING interms of quality.

quality = how good and how true to the octane rating it is. Also it relates to the possibility of any outside contamination in the fuel or fuel tanks which its stored.

octane or grade (ie 93) relates to its resistance to combustion with out spark and a few other things.

 

[vermilion]

fuel filter could be poop too. does it have a previous tune on the engine also?

 

[Lee12609]

dirty MAF

 

[Ninety8stang]

Do you lose power when you notice the ping?

 

[AaRoN]

Use 87 octane. 89 and 93 is just a waste of money.

 

[dirtysnowball302]

these cars are bad for pinging an detonation any ways. its safer to us 93 octan.. dont be a cheap a** just to save 3.00 bucks here an there.

 

[xsoutherngun89x]

did it do it before the dealer did the tune-up? if not id start there, whatever they swapped out was possibly not done correctly