If a plugs have not been changed on a 100,000 mile motor, like on my 2.8 v6 in my audi, could this cause detonation?? with no load on the motor, it runs smooth all the way through the rpms. with a load and hard acceleration (merging onto the highway) I can hear a det. sound or almost a ticking sound. not an exhaust leak, 'cause that would be heard with or without a load on the motor. any ideas??? would a bad knock sensor throw a code?? could a bad ECT sensor cause this problem??

 

If your motor has detonated, then it wouldnt run my friend. 1 bad plug wouldnt make you motor detonate. You'd just lose a cylinder, but it really wouldnt cause catastrophic failure.

 

detonation is also known as pre-ignition, and yes it would run.

 

Then you are talking about a totally different detonation. Most people think youre talking about catastrophic failure when you say that, not the burning/explosion of the fuel.

So you think your pistons are knocking? Does the noise ever go away or is it just on start up?

 

When I think of detonation, as others do i think, i think of pre ignition-the common result of running lean, or even engine knock, but not like an IED detonating in Iraq... If your plugs have been in for 100k miles, step 1 would be to replace those!

 

it is only when the motor is under a load. running or revving high in a static condition it never makes the noise.

 

any recommedations on a particular plug for this car. 12valve 2.8

 

haha ... Your plugs are fried... Get new one's asap and go easy on it till you get that done. Your plugs cant take the heat anymore, and if you keep pushing them they can melt if they havent already started to do that already... Worst case would be the electrode ground melts/snaps off and goes bye bye into the cylinder head which = bye bye engine.

 

it wouldnt be much of a loss, its only a 12v haha

 

NGK BKUR6ET-10 is the replacement for you I think. Or Bosch #FR7LDC+. Something like that...