Please help!

[V6ThatKicks]

I have a 1998 Mustang V6 it has been the best car for many years, but recently I have come across a sound coming from the engine it is only when the engine is hot and I press the gas. My stang has recently hit 100,000 miles and hope that it will go 100,000 more I change the oil regularly and don't get on it too hard. The sound is a more dieseling sound more than anything else and I am hoping it is not too serious. Please help.

 

[AP1995V6]

May be lifter/rocker problems.

 

[TheCrazy1]

Hey, you mentioned a dieseling noise... is this when you get on it hard or just when the engine speeds up under light load? I was going to mention that it could be 'pinging'. If you suspect this, you could try using some higher octane gas and see if it clears up. Sometimes carbon builds up in the combustion chamber and increases the compression ratio, which leads to pinging with regular gas. Also you said it does it when it's hot, preignition is most likely to occur with a hot engine as well. There's several likely causes of pinging. Mine did it from a bad mass air flow sensor causing a lean mixture. Hopefully all goes well with it!